# Patent

## Title
Hardware resource having an optimistic policy and a pessimistic policy

## Abstract

Processor resource management devices and methods are disclosed. In some implementations, a device includes a processor, a hardware resource, and a resource manager operable to compare a first execution of one or more instructions pursuant to an optimistic resource management policy and a second execution of one or more instructions pursuant to a pessimistic resource management policy, the optimistic resource management policy assuming that less than an optimistic level of at least one error will occur during the first execution, and the pessimistic resource management policy assuming that greater than a pessimistic level of the at least one error will occur during the second execution. Based at least partially on the comparison, the resource manager selects a resource management policy from between the optimistic and pessimistic resource management policies, and associates the selected resource management policy with the one or more instructions.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is related to and claims the benefit of the earliest available effective filing date(s) from the following listed application(s) (the “Related Applications”) (e.g., claims earliest available priority dates for other than provisional patent applications or claims benefits under 35 USC §119(e) for provisional patent applications, for any and all parent, grandparent, great-grandparent, etc. applications of the Related Application(s)), and incorporates by reference in its entirety all subject matter of the following listed application(s) (in the event of any inconsistencies between the instant application and an application incorporated by reference, the instant application controls):
1. For purposes of the USPTO extra-statutory requirements, the present application constitutes a continuation-in-part of U.S. patent application Ser. No. 11/214,458 entitled MULTIPROCESSOR RESOURCE OPTIMIZATION, naming Bran Ferren, W. Daniel Hillis, Nathan P. Myhrvold, Clarence T. Tegreene, and Lowell L. Wood, Jr. as inventors, filed under Attorney Docket No. 0805-027-001B-000000 on Aug. 29, 2005 now U.S. Pat No. 7,539,852, which is currently co-pending, or is an application of which a currently co-pending application is entitled to the benefit of the filing date.
2. For purposes of the USPTO extra-statutory requirements, the present application constitutes a continuation-in-part of U.S. patent application Ser. No. 11/214,459 entitled PREDICTIVE PROCESSOR RESOURCE MANAGEMENT, naming Bran Ferren, W. Daniel Hillis, William Mangione-Smith, Nathan P. Myhrvold, Clarence T. Tegreene, and Lowell L. Wood, Jr. as inventors, filed under Attorney Docket No. 0805-027-002-000000 on Aug. 29, 2005 now U.S. Pat No. 7,774,558, which is currently co-pending, or is an application of which a currently co-pending application is entitled to the benefit of the filing date.
3. For purposes of the USPTO extra-statutory requirements, the present application constitutes a continuation of U.S. patent application Ser. No. 11/214,449 entitled PREDICTIVE PROCESSOR RESOURCE MANAGEMENT, naming Bran Ferren, W. Daniel Hillis, William Mangione-Smith, Nathan P. Myhrvold, Clarence T. Tegreene, and Lowell L. Wood, Jr. as inventors, filed under Attorney Docket No. 0805-027-001A-000000 on Aug. 29, 2005, which is currently co-pending, or is an application of which a currently co-pending application is entitled to the benefit of the filing date, and which application subsequently issued as U.S. Pat. No. 7,539,852 on May 26, 2009.
The United States Patent Office (USPTO) has published a notice to the effect that the USPTO's computer programs require that patent applicants reference both a serial number and indicate whether an application is a continuation or continuation-in-part. Stephen G. Kunin, Benefit of Prior-Filed Application, USPTO Official Gazette Mar. 18, 2003. The present Applicant Entity (hereinafter “Applicant”) has provided above a specific reference to the application(s) from which priority is being claimed as recited by statute. Applicant understands that the statute is unambiguous in its specific reference language and does not require either a serial number or any characterization, such as “continuation” or “continuation-in-part,” for claiming priority to U.S. patent applications. Notwithstanding the foregoing, Applicant understands that the USPTO's computer programs have certain data entry requirements, and hence Applicant is designating the present application as a continuation-in-part of its parent applications as set forth above, but expressly points out that such designations are not to be construed in any way as any type of commentary and/or admission as to whether or not the present application contains any new matter in addition to the matter of its parent application(s). All subject matter of the Related Applications and of any and all parent, grandparent, great-grandparent, etc. applications of the Related Applications is incorporated herein by reference to the extent such subject matter is not inconsistent herewith.


SUMMARY
Systems and processes for processor resource management are disclosed. For example, in at least some implementations, a device may include a processor, a hardware resource operatively associated with the processor, and a resource manager. The resource manager may be operable to: compare a first execution of one or more instructions pursuant to an optimistic resource management policy applied to the hardware resource and a second execution of one or more instructions pursuant to a pessimistic resource management policy applied to the hardware resource, the optimistic resource management policy assuming that less than an optimistic level of at least one error will occur during the first execution, and the pessimistic resource management policy assuming that greater than a pessimistic level of the at least one error will occur during the second execution; based at least partially on the comparison, select a resource management policy from between the optimistic and pessimistic resource management policies; and associate the selected resource management policy with the one or more instructions. resource management policy from between the optimistic and pessimistic resource management policies; and associate the selected resource management policy with the one or more instructions.
These and various other features as well as advantages of the present invention will be apparent from a reading of the following detailed description and a review of the associated drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
Aspects of the invention, together with features and advantages thereof, may be understood by making reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like referenced numerals identify like elements, and wherein:
FIG. 1 illustrates a partial view of an exemplary device in which embodiments may be implemented;
FIG. 2 illustrates an exemplary operational flow in which embodiments may be implemented;
FIG. 3 illustrates alternative embodiments of the operation 210 of FIG. 2;
FIG. 4 illustrates alternative embodiments of the operation 220 of FIG. 2;
FIG. 5 illustrates alternative embodiments of the operation 230 of FIG. 2;
FIG. 6 illustrates alternative embodiments of the operational flow of FIG. 2;
FIG. 7 illustrates an exemplary operational flow in which embodiments may be implemented;
FIG. 8 illustrates an exemplary operational flow in which embodiments may be implemented;
FIG. 9 illustrates alternative embodiments of the operation of FIG. 8;
FIG. 10 illustrates an exemplary embodiment of a device in which embodiments may be implemented;
FIG. 11 illustrates a partial view of an exemplary operational flow in which embodiments may be implemented;
FIG. 12 illustrates alternative embodiments of the operation of FIG. 11;
FIG. 13 illustrates alternative embodiments of the operation of FIG. 11;
FIG. 14 illustrates alternative embodiments of the operational flow of FIG. 11;
FIG. 15 illustrates a partial view of an exemplary operational flow in which embodiments may be implemented;
FIG. 16 illustrates a partial view of an exemplary operational flow in which embodiments may be implemented;
FIG. 17 illustrates alternative embodiments of the operation of FIG. 11;
FIG. 18 illustrates a partial view of an exemplary operational flow in which embodiments may be implemented; and
FIG. 19 illustrates alternative embodiments of the operation 920 of FIG. 18.



DETAILED DESCRIPTION
In the following detailed description of exemplary embodiments, reference is made to the accompanying drawings, which form a part hereof. In the several figures, like referenced numerals identify like elements. The detailed description and the drawings illustrate exemplary embodiments. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. The following detailed description is therefore not to be taken in a limiting sense, and the scope of the claimed subject matter is defined by the appended claims.
FIG. 1 illustrates a partial view of an exemplary device 100 in which embodiments may be implemented. The device includes a processor 110 and a hardware resource 120 associated with the processor. The hardware resource may be any hardware resource associated and/or associatable with a processor. In an embodiment, the hardware resource may include one or more caches, illustrated as a cache 1 (121), a cache 2 (122), and through a cache N (123). Also, the hardware resource may include a branch predictor 124.
In another embodiment, the hardware resource 120 may include any other resource associated with the processor, illustrated as other resource 126. In a further embodiment, the hardware resource includes an off-chip resource, illustrated as an off-chip resource 128. For example, the cache 1 (121) may be an on-chip L1 cache and the cache 2 (122) may be an on-chip L2 cache. By way of further example, the off-chip resource 128 may be an off-chip L2 cache.
The device also includes a resource manager 140, and/or a processor control unit 150. The processor control unit 150 may be an element of the processor 110, or may be an element separate from the processor. In an embodiment, the processor, the processor control unit, and at least one of the hardware devices are formed in a single chip, illustrated as the processor chip 101. In another embodiment, the processor is formed in a first chip and at least one of the hardware resources formed in a second chip.
The resource manager 140 includes an operability to compare an execution of an instruction group pursuant to a first resource management policy applied to the hardware resource and an execution of the instruction group pursuant to a second resource management policy applied to the hardware resource. The resource manager also includes an operability to select from the first resource management policy and the second resource management policy a resource management policy likely to provide a substantially optimum execution of the instruction group. The resource manager further includes an operability to associate the selected resource management policy with the instruction group.
In an embodiment, an “instruction group” may include a functional instruction, a branching instruction, a memory instruction, and/or other instruction that may be executed by a processor. In another embodiment, an instruction group includes a statement or a portion of a statement in a program. In a further embodiment, an instruction group includes at least two statements from a program. A program may include any type of a program, from several lines of instructions, to an application, and to an operating system. In an embodiment, an instruction group may include a decoded instruction, a translated instruction, and/or a micro-operation (a portion of a translated instruction).
In an embodiment, the hardware resource includes a hardware resource logically associated with the processor. In another embodiment, the hardware resource includes a hardware resource physically associated with the processor. In a further embodiment, the hardware resource includes a hardware resource managed by the processor. In an embodiment, the hardware resource managed by the processor includes at least one of a memory, a cache, a bus, a register-file port, and a functional unit.
In an embodiment, the resource manager operable to compare includes a resource manager operable to compare according to preselected criterion. The preselected criterion includes at least one of a successful completion of the instruction group, an unsuccessful completion of the instruction group, an uncertain completion of the instruction group, an exception, a time to execute the instruction group, a successful hit, an unsuccessful hit, a hit ratio, correctly predicting a branch taken, incorrectly predicting a branch taken, correctly predicting a branch not taken, and/or incorrectly predicting a branch not taken.
In another embodiment, the resource manager operable to select from the first resource management policy and the second resource management policy a resource management policy likely to provide a substantially optimum execution of the instruction group includes resource manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group according to a preselected criterion. In an embodiment, the preselected criterion includes a criterion responsive to an output of the compare an execution of an instruction group pursuant to a first resource management policy applied to the hardware resource and an execution of the instruction group pursuant to a second resource management policy applied to the hardware resource. In a further embodiment, the preselected criterion includes a criterion responsive to at least one of a successful completion of the instruction group, an unsuccessful completion of the instruction group, an uncertain completion of the instruction group, an exception, a time to execute the instruction group, a successful hit, an unsuccessful hit, a hit ratio, correctly predicting a branch taken, incorrectly predicting a branch taken, correctly predicting a branch not taken, and/or incorrectly predicting a branch not taken.
In an embodiment, the resource manager operable to select from the first resource management policy and the second resource management policy a management policy likely to provide a substantially optimum execution of the instruction group includes a resource manager operable to compare the execution of the instruction group pursuant to the first management policy and the execution of the instruction group pursuant to the second management policy applied to the resource.
In another embodiment, the first resource management policy includes an optimistic management policy. In a further embodiment, the optimistic resource management policy includes an optimistic resource management policy that assumes that the instruction group will execute in a substantially optimal manner. In an embodiment, the optimistic resource management policy assumes that the instruction group will execute in a substantially optimal manner includes an optimistic resource management policy that assumes that less than a preselected level of at least one error will occur during execution of the instruction group. In a further embodiment, the at least one error includes an occurrence of at least one of a hardware error, a fetch error, a memory error, a cache miss, a software error, an arithmetic overflow, a stale datum, a branch prediction error, an attempt to access forbidden memory, and/or an inability of an operating system to grant a request.
In an embodiment, the second resource management policy includes a pessimistic resource management policy. In another embodiment, the pessimistic resource management policy includes a pessimistic resource management policy that assumes that the instruction group will execute in a substantially sub-optimal manner. In a further embodiment, the pessimistic resource management policy assumes that the instruction group will execute in a substantially sub-optimal manner includes a pessimistic resource management policy that assumes that greater than a preselected level of at least one error will occur during execution of the instruction group. In an embodiment, the at least one error includes at least one of a hardware error, a fetch error, a memory error, a cache miss, a software error, an arithmetic overflow, a stale datum, a branch prediction error, an attempt to access forbidden memory, and/or an inability of an operating system to grant a request.
In another embodiment, the resource manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group includes a resource manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group according to a preselected criterion. In a further embodiment, the preselected criterion includes at least one of a successful completion of the instruction group, an unsuccessful completion of the instruction group, an uncertain completion of the instruction group, an exception, a time to execute the instruction group, a successful hit, an unsuccessful hit, a hit ratio, correctly predicting a branch taken, incorrectly predicting a branch taken, correctly predicting a branch not taken, and/or incorrectly predicting a branch not taken.
In a further embodiment, the resource manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group includes a resource manager operable to select a management policy predicted as likely to provide a substantially optimum execution of the instruction group. In an embodiment, the resource manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group includes a resource manager operable to select a management policy predicted by a Bayesian method as likely provide a substantially optimum execution of the instruction group. In another embodiment, the resource manager operable to select a management policy predicted by a Bayesian method as likely provide a substantially optimum execution of the instruction group includes resource manager operable to recall historical data from a ghost page. In a further embodiment, the resource manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group includes a resource manager operable to select a management policy predicted by a heuristic as likely provide a substantially optimum execution of the instruction group. In an embodiment, the resource manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group includes a resource manager operable to select a management policy predicted by a learning algorithm as likely provide a substantially optimum execution of the instruction group. In another embodiment, the associate the selected resource management policy with the instruction group includes associate a ghost page indicative of the selected resource management policy with the instruction group.
In an embodiment, a Bayesian method includes any methodology corresponding to or derived from Bayesian theories. In another embodiment, a Bayesian method includes but is not limited to statistics, principles, models, applications, analysis, decisions, inferences, probabilistic modeling, probabilistic reasoning, networks, and/or approaches based at least in part on the work of Thomas Bayes.
In operation, an embodiment provides an optimized configuration of the actual hardware resource 120 and the actual processor 110 when the processor is executing an instruction group. For example, the hardware resource may include an L2 cache. The instruction group is executed by the processor in two passes, a first pass includes application of the first resource management policy to the L2 cache, and a second pass includes application of the second resource management policy to the L2 cache. The execution results are then compared. For example, a comparison may include parameters of execution time and cache misses. One of the two resource management policies is then selected as likely to provide a better execution of the instruction group. The selected resource management policy is then associated with the instruction group in a manner allowing retrieval. The selected resource management policy may be saved in a manner allowing retrieval for a future application to the cache when the processor is scheduled to run the instruction group. For example, the selected resource management policy may be saved in a ghost page associated with at least a portion of the instruction group.
In another embodiment of an operation, the resource may include a dynamic branch predictor, such as the branch predictor 124. As described above, the instruction group is executed by the processor in two passes, a first pass includes application of the first resource management policy to the branch predictor, and a second pass includes application of the second resource management policy to the branch predictor. The execution results are then compared. For example, a comparison may include branching operations correctly predicted. One of the two resource management policies for branch prediction is then selected as likely to provide a better execution of the instruction group. The selected resource management policy is then associated with the instruction group in a manner allowing retrieval. The selected resource management policy may be saved in a manner allowing retrieval for a future application to the branch predictor when the processor is scheduled to run the instruction group.
FIG. 2 illustrates an exemplary operational flow 200 in which embodiments may be implemented. In an embodiment, the operational flow may be executed in the device 100 of FIG. 1. An operation 210 applies a first management policy to a resource managed by a processor and executing an instruction block in the processor. An operation 220 applies a second management policy to the resource and executing the instruction block in the processor. An operation 230 selects a management policy likely to provide a substantially optimum execution of the instruction group from the first management policy and the second management policy.
FIG. 3 illustrates alternative embodiments of the operation 210 of FIG. 2. The operation 212 selects the first management policy from at least two candidate management policies. The operation 214 obtains a first result of the executing an instruction block in the processor. The operation 216 applies an optimistic management policy to the resource. The applying an optimistic management policy to the resource may include applying a resource management policy that assumes that less than a preselected level of at least one error will occur during an execution of the instruction group.
FIG. 4 illustrates alternative embodiments of the operation 220 of FIG. 2. The operation 222 selects the second management policy from at least two candidate management policies. The operation 224 obtains a second result of the executing an instruction block in the processor. The operation 226 applies a pessimistic management policy to the resource. The applying a pessimistic management policy to the resource may include applying a management policy that assumes that more than a preselected level of at least one error will occur during an execution of the instruction group.
FIG. 5 illustrates alternative embodiments of the operation 230 of FIG. 2. The operation 232 selects a management policy likely to provide a substantially optimum execution of the instruction group according to a preselected criterion. The operation 234 compares the execution of the instruction group pursuant to the first management policy and the execution of the instruction group pursuant to the second management policy applied to the resource.
FIG. 6 illustrates alternative embodiments of the operational flow 200 of FIG. 2. The operational flow 242 associates the selected management policy with the instruction group. The operational flow 244 associates a ghost page indicative of the selected management policy with the instruction group.
In an alternative embodiment, the exemplary operational flow 200 may include an iterative method where the operational flow 200 is repeated at least twice to test at least three resource management policies, and allow a selecting from the at least three resource management policies.
Returning to FIG. 1, an alternative embodiment of the exemplary device 100 includes the processor 110 having the hardware resource 120 associated with the processor. In the alternative embodiment, the processor control unit 150 includes a processor control unit operable to compare an execution of an instruction group pursuant to an optimistic resource management policy applied to the hardware resource and an execution of the instruction group pursuant to a pessimistic resource management policy applied to the hardware resource. The alternative embodiment of the processor control unit also includes a processor control unit operable to select from the optimistic resource management policy and the pessimistic resource management policy a resource management policy likely to provide a substantially optimum execution of the instruction group. The alternative embodiment of the processor control unit further includes a resource manager operable to associate the selected resource management policy with the instruction group. In an embodiment, the processor and the processor control unit are formed on a single chip.
In a further embodiment, the optimistic resource management policy assumes that the instruction group will execute in a substantially optimal manner. In another embodiment, the optimistic resource management policy assumes that the instruction group will execute in a substantially optimal manner includes an optimistic resource management policy that assumes that less than a preselected level of at least one error will occur during execution of the instruction group. In an embodiment, the at least one error includes an occurrence of at least one of a hardware error, a fetch error, a memory error, a cache miss, a software error, an arithmetic overflow, a stale datum, a branch prediction error, an attempt to access forbidden memory, and/or an inability of an operating system to grant a request.
In an embodiment, the pessimistic resource management policy assumes that the instruction group will execute in a substantially sub-optimal manner. In another embodiment, the pessimistic resource management policy assumes that the instruction group will execute in a substantially sub-optimal manner includes a pessimistic resource management policy that assumes that greater than a preselected level of at least one error will occur during execution of the instruction group. In a further embodiment, the at least one error includes at least one of a hardware error, a fetch error, a memory error, a cache miss, a software error, an arithmetic overflow, a stale datum, a branch prediction error, an attempt to access forbidden memory, and/or an inability of an operating system to grant a request.
FIG. 7 illustrates an exemplary operational flow 300 in which embodiments may be implemented. The operation 310 applies an optimistic cache management policy to a cache managed by a processor, executing an instruction block in the processor, and acquiring a context of the execution while the optimistic cache management policy is applied. The operation 320 applies a pessimistic cache management policy to the cache, executing the instruction block in the processor, and acquiring a context of the execution while the pessimistic cache management policy is applied. The operation 330 selects a cache management policy likely to provide a substantially optimum execution of the instruction group from the optimistic cache management policy and the pessimistic cache management policy. The operation 340 associates a ghost page indicative of the selected cache management policy and of the context of the execution during application of the selected cache management policy with the instruction group.
Further returning to FIG. 1, another alternative embodiment of the exemplary device 100 includes the processor 110 having the hardware resource 120 associated with the processor. In the alternative embodiment, the processor control unit 150 includes a processor control unit operable to fetch an instruction to be executed in the processor. In an embodiment, the operation to fetch the instruction to be executed in the processor may include facilitating the operation to fetch the instruction to be executed in the processor. In another embodiment, the operation to fetch the instruction to be executed in the processor may include issuing a signal timing the operation to fetch the instruction to be executed in the processor. The processor control unit is also operable to receive a previously selected resource management policy associated with the instruction, the resource management policy having been selected as likely to provide a substantially optimum execution of an instruction group that includes the instruction, and having been selected from a optimistic resource management policy and a pessimistic resource management policy. The processor control unit is further operable to apply the previously selected resource management policy to the resource. In another alternative embodiment, the processor control unit is also operable to enable the processor to execute the instruction. In a further alternative embodiment, the processor control unit is operable to enable the processor to execute the instruction, and apply another resource management policy to the hardware resource.
In operation, an embodiment obtains a previously selected optimized configuration of the hardware resource 120 for the processor 110 in conjunction with executing the instruction group. When the processor is preparing to execute an instruction group, the processor control unit receives a previously selected resource management policy associated with the instruction. In an embodiment, the previously selected resource management policy may include a previously selected resource management policy provided by the method 200 of FIG. 2 and/or the method 300 of FIG. 7. For example, the hardware resource may include the branch predictor 124, and the previously selected resource management policy may include a previously selected resource management policy selected as likely to provide a substantially optimum execution of the instruction. The processor control unit applies the previously selected resource management policy to the hardware resource, such as the branch predictor. The instruction is executed by the processor with the hardware resource, such as the branch predictor, managed by the previously selected resource management policy. This is expected to provide an optimized execution of the instruction over an execution of the instruction with a resource management policy applied to the hardware resource that is not likely to provide a substantially optimum execution of the instruction group.
FIG. 8 illustrates an exemplary operational flow 400 in which embodiments may be implemented. An operation 410 fetches an instruction to be executed in a central processor unit having an associated resource. An operation 420 receives a previously selected resource management policy associated with the instruction. The resource management policy having been selected as likely to provide a substantially optimum execution of an instruction group that includes the instruction, and having been selected from a optimistic resource management policy and a pessimistic resource management policy. An operation 430 applies the previously selected resource management policy to the resource. An operation 440 executes the instruction in the central processor unit. In a further alternative embodiment, an operation (not shown) executes the instruction in the central processor unit and then applies another resource management policy to the hardware resource.
FIG. 9 illustrates alternative embodiments of the operation 410 of FIG. 8. An operation 412 fetches an instruction to be executed in a central processor unit having an associated cache resource. An operation 416 fetches an instruction to be executed in a central processor unit having an associated branch predictor resource. In an alternative embodiment of the operation 410, at an operation 414, the associated cache resource includes one of an on-chip cache or an off-chip cache.
FIG. 10 illustrates an exemplary embodiment of a device 500 in which embodiments may be implemented. The device includes a first processor 510, a second processor 514, and a Nth Processor 518. The device also includes at least one hardware resource 220 associated with the processor. The at least one hardware resource may be any hardware resource associated and/or associatable with a processor. In an embodiment, the at least one hardware resource includes a first cache 521 associated with the first processor and a second cache 522 associated with the second processor. In another embodiment, the at least one hardware resource may include an Nth cache 524, a first branch predictor 526, an second branch predictor 527, other resource(s) 528, and an off-processor-chip resource 529. The device also includes a cache manager 540 operable to manage the caches 521, 522, and 524, and a hardware resource manager operable to manage other hardware, such as the branch predictor, the other resource(s), and the off-processor-chip resource(s).
The device 500 also includes a cache manager 540 implemented in a hardware-logic. The cache manager is operable to compare an execution of an instruction group by the first processor 510 while a first cache management policy is applied to the first cache 521 and an execution of the instruction group by the second processor 514 while a second cache management policy is applied to the second cache 522. The cache manager is also operable to select a cache management policy likely to provide a substantially optimum execution of the instruction group from the first cache management policy and the second cache management policy. The cache manager is further operable to associate the selected cache management policy with the instruction group.
In an embodiment, the first processor 510 and the second processor 514 are implemented on a single chip. In another embodiment the first cache 521 and the second cache 522 are a logical partition of a physical memory 523. In a further embodiment, the first cache and second cache are accessible by both the first and second processor. In an embodiment, the first cache includes an L2 cache and the second cache includes an L2 cache. In another embodiment, the first processor and the cache manager are formed on a single chip 501.
In an embodiment, the cache manager operable to associate the selected cache management policy with the instruction group includes a cache manager operable to associate a ghost page indicative of the selected management policy with the instruction group. In a further embodiment, the cache manager operable to compare includes a cache manager operable to compare according to preselected criterion. In an embodiment, the preselected criterion includes at least one of a successful completion of the instruction group, an unsuccessful completion of the instruction group, an uncertain completion of the instruction group, an exception, a time to execute the instruction group, a successful hit, an unsuccessful hit, a hit ratio, correctly predicting a branch taken, incorrectly predicting a branch taken, correctly predicting a branch not taken, and/or incorrectly predicting a branch not taken.
In an embodiment, the first cache management policy assumes that the instruction group will execute in a substantially optimal manner. In another embodiment, the first cache management policy that assumes that the instruction group will execute in a substantially optimal manner includes a first cache management policy that assumes that less than a preselected level of at least one error will occur during execution of the instruction group. In a further embodiment, the at least one error includes an occurrence of at least one of a hardware error, a fetch error, a memory error, a cache miss, a software error, an arithmetic overflow, a stale datum, a branch prediction error, an attempt to access forbidden memory, and/or an inability of an operating system to grant a request.
In an embodiment, the second cache management policy assumes that the instruction group will execute in a substantially sub-optimal manner. In another embodiment, the second cache management policy assumes that the instruction group will execute in a substantially sub-optimal manner includes a second cache management policy that assumes that greater than a preselected level of at least one error will occur during execution of the instruction group. In a further embodiment, the at least one error includes at least one of a hardware error, a fetch error, a memory error, a cache miss, a software error, an arithmetic overflow, a stale datum, a branch prediction error, an attempt to access forbidden memory, and/or an inability of an operating system to grant a request.
In an embodiment, the cache manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group includes a cache manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group according to a preselected criterion. In another embodiment, the preselected criterion includes at least one of a successful completion of the instruction group, an unsuccessful completion of the instruction group, an uncertain completion of the instruction group, an exception, a time to execute the instruction group, a successful hit, an unsuccessful hit, a hit ratio, correctly predicting a branch taken, incorrectly predicting a branch taken, correctly predicting a branch not taken, and/or incorrectly predicting a branch not taken.
In an embodiment, the cache manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group includes a cache manager operable to select a management policy predicted as likely to provide a substantially optimum execution of the instruction group. In another embodiment, the cache manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group includes a cache manager operable to select a management policy predicted by a Bayesian method as likely provide a substantially optimum execution of the instruction group. In a further embodiment, the cache manager operable to select a management policy predicted by a Bayesian method as likely provide a substantially optimum execution of the instruction group includes cache manager operable to recall historical data from a ghost page.
In an embodiment, the cache manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group includes a cache manager operable to select a management policy predicted by a heuristic as likely provide a substantially optimum execution of the instruction group. In another embodiment, the cache manager operable to select a management policy likely to provide a substantially optimum execution of the instruction group includes a cache manager operable to select a management policy predicted by a learning algorithm as likely provide a substantially optimum execution of the instruction group.
In operation, an embodiment of the device 500 provides an optimization of a processor and a cache when executing an instruction group. For example, when the first cache 521 and the second cache 522 are logical partitions of a physical memory, different cache management policies may be tried for the instruction group. The execution results of the instruction group are compared, and a cache management policy selected that provides a substantially optimum execution selected in response to the comparison. For example, the first and second management policies may provide different cache sizes. The instruction group may be executed on both processors while the different cache sizes are applied to the first cache and the second cache. The executions are compared, and a cache management policy selected that works better, i.e., provides a substantially optimum execution of the instruction group. In another example, the first and second management policies may provide different flush rates. A selected cache management policy is associated with the instructions group, for example by using a ghost page, for a use in a future execution of the instruction group.
Continuing with FIG. 10, FIG. 10 illustrates another exemplary embodiment of a device 500 in which an embodiment may be implemented. The device includes a first processor 510 having an associated first hardware resource and a second processor 514 having an associated second hardware resource. In an embodiment, the associated first hardware resource includes a first branch predictor 526 and the associated second hardware resource includes a second branch predictor 527. In another embodiment, the first and second hardware resources may include a memory, a bus, a register-file port, and/or a function unit, which are collectively illustrated as other resource(s) 528 and/or off-chip resource(s) 529.
The device 500 also includes hardware resource manager 542 implemented in a hardware-logic. The resource manager is operable to compare an execution of an instruction group by the first processor 510 while a first resource management policy is applied to the first hardware resource and an execution of the instruction group by the second processor 527 while a second resource management policy is applied to the second hardware resource. Continuing with an above example, the first hardware resource may include the first branch predictor 526 and the second hardware resource includes the second branch predictor 527. In an alternative embodiment, the first hardware resource includes a first off-processor-chip cache and the second hardware resource includes a second off-processor-chip cache 529.
The resource manager is also operable to select from the first resource management policy and the second resource management policy a resource management policy likely to provide a substantially optimum execution of the instruction group. The resource manager is further operable to associate the selected resource management policy with the instruction group. In an embodiment, the resource manager is associated with the first processor. In another embodiment, the resource manager is associated with the first processor and the second processor.
FIG. 11 illustrates a partial view of an exemplary operational flow 550 in which embodiments may be implemented. In an embodiment, the operational flow may be executed in the device 500 of FIG. 10. An operation 560 applies a first resource management strategy to a first resource associated with a first processor and executing an instruction block in the first processor. An operation 570 applies a second resource management strategy to a second resource of a similar type as the first resource and executing the instruction block in the second processor. An operation 580 selects a resource management strategy likely to provide a substantially optimum execution of the instruction group from the first resource management strategy and the second resource management strategy.
FIG. 12 illustrates alternative embodiments of the operation 560 of FIG. 11. An operation 562 applies a first resource management strategy to a first resource associated with a first processor includes applying a first resource management strategy to a cache associated with a first processor. An operation 564 applies a first resource management strategy to a first resource associated with a first processor includes applying a first resource management strategy to a register associated with a first processor. An operation 566 applies a first resource management strategy to a first resource associated with a first processor includes applying a first resource management strategy to a functional unit associated with a first processor. An operation 568 applies a first resource management strategy to a branch predictor associated with a first processor.
FIG. 13 illustrates alternative embodiments of the operation 580 of FIG. 11. An operation 582 selects a resource management strategy likely to provide a substantially optimum execution of the instruction group according to preselected criterion. In an alternative embodiment, the operation 582 may include an operation 584. At the operation 584, the preselected criterion includes at least one of a successful completion of the instruction group, an unsuccessful completion of the instruction group, an uncertain completion of the instruction group, an exception, a time to execute the instruction group, a successful hit, an unsuccessful hit, a hit ratio, correctly predicting a branch taken, incorrectly predicting a branch taken, correctly predicting a branch not taken, and/or incorrectly predicting a branch not taken. An operation 586 applies 584a first resource management strategy to a first resource associated with a first processor includes applying an optimistic resource management strategy to a first resource associated with a first processor. In an alternative embodiment, the operation 586 may include an operation 588. At the operation 588, the optimistic resource management strategy assumes that the instruction group will execute in a substantially optimal manner. An operation 590 applies a pessimistic resource management strategy to a second resource of a similar type as the first resource. In an alternative embodiment, the operation 590 may include an operation 592. At the operation 592, the pessimistic resource management strategy assumes that the instruction group will execute in a substantially sub-optimal manner.
FIG. 14 illustrates alternative embodiments 595 of the operational flow 550 of FIG. 11. An operation 596 592 associates the selected resource management strategy with the instruction group. An operation 598 associates a ghost page indicative of the selected resource management strategy with the instruction group.
FIG. 15 illustrates a partial view of an exemplary operational flow 600 in which embodiments may be implemented. An operation 610 applies an optimistic cache management strategy to a first cache associated with a first processor, executing an instruction block in the first processor, and acquiring a context of the first processor execution. An operation 620 applies a pessimistic cache management strategy to a second cache associated with a second processor, executing the instruction block in the second processor, and acquiring a context of the second processor execution. An operation 630 selects from the optimistic cache management strategy and the pessimistic cache management strategy a cache management strategy likely to provide a substantially optimum execution of the instruction group. An operation 640 associates the instruction group with a ghost page indicative of the selected cache management strategy and of the context of the execution during the application of the selected cache management strategy.
Returning to FIG. 10, FIG. 10 also illustrates a further exemplary embodiment of the device 500. The device includes a processor, such as the first processor 510, having an associated first hardware resource, such as the first branch predictor 526, and a present context. The device also includes a control unit associated with the first processor core, such as for example the cache manager 540 or the hardware resource manager 542. The control unit is operable to fetch an instruction for execution by the processor. The control unit is also operable to receive a previously selected resource management policy associated with the instruction, the resource management policy selected as likely to provide a substantially optimum execution of an instruction group that includes the instruction, and further selected from a optimistic resource management policy and a pessimistic resource management policy. The control unit is further operable to apply the previously selected resource management policy to the resource, and cause the processor to execute the instruction.
In an alternative embodiment, the control unit operable to apply the previously selected resource management policy to the resource includes a control unit operable to apply the previously selected resource management policy only if a predetermined similarity exists between the present context of the processor and the context existing when the selected resource management policy was selected. Otherwise, the control unit does not apply the previously selected resource management policy to the resource.
FIG. 16 illustrates a partial view of an exemplary operational flow 700 in which embodiments may be implemented. In an embodiment, the operational flow may be executed in the device 500 of FIG. 10. In another embodiment, an operation 710 fetches an instruction to be executed by a processor core of a chip having at least two processor cores that each have access to a resource. An operation 720 receives a previously selected resource management policy associated with the instruction. The resource management policy having been selected as likely to provide a substantially optimum execution of an instruction group that includes the instruction, and having further been selected from a optimistic resource management policy and a pessimistic resource management policy. An operation 730 applies the previously selected resource management policy to the resource. An operation 740 executes the instruction by the processor core.
FIG. 17 illustrates alternative embodiments of the operation 710 of FIG. 11. An operation 712 fetches an instruction to be executed by a processor core of a chip having at least two processor cores that each have an access to a cache resource. In another embodiment, the operation 712 includes an operation 714, where cache resource includes one of an on-chip cache or an off-chip cache. An operation 716 fetches an instruction to be executed by a processor core of a chip having at least two processor cores that each have access to a branch predictor. In another embodiment, the operation 716 includes an operation 718, where the branch predictor includes static branch predictor or a dynamic branch predictor.
Returning to FIG. 1, an alternative embodiment of the exemplary device 100 includes the processor 110 and the processor-associated hardware resource 120. The processor is operable to execute an instruction group. The resource manager 140 is operable to implement a resource management policy for the hardware resource with respect to an execution of the instruction group, the resource management policy responsive to a prediction of a performance of the hardware resource based at least in part on a historical performance of the hardware resource.
In an embodiment, the processor and the associated hardware resource are formed on a single chip. In another embodiment, the processor and resource manager are formed on a single chip. In a further embodiment, the hardware resource includes a cache, such as the cache 1 (121) or an off-chip cache illustrated as the off-chip resource 128. In an embodiment, the hardware resource includes a logical partition of a cache, such as the first cache 521 of the physical memory device 523 of FIG. 10. In another embodiment, the hardware resource includes the branch predictor 124, which may be a dynamic branch predictor. In a further embodiment, the hardware resource includes a hardware resource logically associated with the processor. In an embodiment, the hardware resource includes a hardware resource physically associated with the processor. In another embodiment, the hardware resource associated with the processor includes a hardware resource controlled by the processor.
In an embodiment, the resource management policy responsive to a prediction of a future performance of the hardware resource based at least in part on a historical performance of the hardware resource includes a resource management policy responsive to a prediction of a future performance of the hardware resource based at least in part on a historical performance of the hardware resource during an execution of the instruction group. By way of illustrative example, in an embodiment, a historical performance of the hardware resource may include a branch being taken an average 90% of the time over 1000 executions of the instruction group. The resource management policy may then include a prediction that the branch is taken. In another embodiment, the resource management policy responsive to a prediction of a performance of the hardware resource based at least in part on a historical performance of the hardware resource includes a resource management policy responsive to a prediction of a performance of the hardware resource based at least in part on a historical performance of the hardware resource and an indicia of confidence. Continuing with the above illustrative example, an indicia of confidence may include a high indicia of confidence because the branch has been taken 99% of the time in the last 10 executions of the instruction group. The resource management policy may then include a prediction that the branch is taken unless two subsequent instances of branch prediction error occur, resulting in a low indicia of confidence. Alternatively, an indicia of confidence may include a low indicia of confidence because the branch has been taken only 15% of the time in the last 10 executions of the instruction group. The resource management policy may then include a prediction that the branch is never taken. In another embodiment, the resource management policy responsive to a prediction of a performance of the hardware resource based at least in part on a historical performance of the hardware resource includes a resource management policy responsive to a prediction of a performance of the hardware resource based at least in part on a historical performance of the hardware resource and a saved indicia of confidence in the prediction of a performance of the hardware resource.
In a further embodiment, the resource management policy formulated in response to a prediction of a performance of the hardware resource based at least in part on a historical performance of the hardware resource includes a resource management policy formulated in response to a prediction of a performance of the hardware resource as likely to provide a substantially optimum execution of the instruction group. For example, the hardware resource may include a cache and the resource management policy includes a cache flush rate. In an embodiment, the resource management policy formulated in response to a prediction of a performance of the hardware resource based at least in part on a historical performance of the hardware resource includes a resource management policy formulated in response to a prediction of a performance of the hardware resource as likely to provide a substantially optimum execution of the instruction group as measured by a preselected criterion. In a further embodiment, the preselected criterion includes at least one of a successful completion of the instruction group, an unsuccessful completion of the instruction group, an uncertain completion of the instruction group, an exception, a time to execute the instruction group, a successful hit, an unsuccessful hit, a hit ratio, correctly predicting a branch taken, incorrectly predicting a branch taken, correctly predicting a branch not taken, and/or incorrectly predicting a branch not taken.
In an embodiment, the resource management policy formulated in response to a prediction of a performance of the hardware resource based at least in part on a historical performance of the hardware resource includes a resource management policy formulated in response to a prediction of a performance of the hardware resource based at least in part on a Bayesian method. In another embodiment, the resource management policy formulated in response to a prediction of a performance of the hardware resource based at least in part on a historical performance of the hardware resource includes a resource management policy formulated in response to a prediction of a performance of the hardware resource based at least in part on a heuristic algorithm. In a further embodiment, the resource management policy formulated in response to a prediction of a performance of the hardware resource based at least in part on a historical performance of the hardware resource includes a resource management policy formulated in response to a prediction of a performance of the hardware resource based at least in part on a learning algorithm. In an embodiment, the resource manager includes a resource manager operable to recall historical data from a ghost page.
In another embodiment, the device 100 further includes a storage device operable to save the historical performance of the hardware resource. In a further embodiment, the storage device operable to save the historical performance of the hardware resource includes a storage device operable to save the historical performance of the hardware resource and a measure of confidence in a prediction based on the historical performance.
FIG. 18 illustrates a partial view of an exemplary operational flow 900 in which embodiments may be implemented. In an embodiment, the operational flow may be executed in the device 900 of FIGS. 1 and/or 10. In another embodiment, an operation 910 receives a historical performance indicia of a hardware resource associated with a processor operable to execute an instruction group. An operation 920 predicts a future performance of the hardware resource based at least in part on the historical performance indicia of the hardware resource. An operation 930 establishes a resource management policy responsive to the predicting a future performance of the hardware resource. An operation 940 implements the resource management policy in the hardware resource for an execution of the instruction group by the processor.
FIG. 19 illustrates alternative embodiments of the operation 920 of FIG. 18. An operation 922 predicts a future performance of the hardware resource at least in part based on the historical performance indicia of the hardware resource corresponding to an execution of the instruction group. An operation 924 predicts a future performance of the hardware resource based at least in part on the historical performance of the hardware resource and a confidence indicia.
Other embodiments are directed toward utilizing and/or optimizing data handling, which may be by a data class. In some instances, a data class includes certain data items (datum, byte, bit, a block of things that are associated together) that are used once and never again. In other instances, a data class includes certain data items are used constantly but never written and/or infrequently written. In further data classes, data items are constantly read and written to, or other data items are often being written but never read. A data manager (which may/may not be associated with and/or part of a resource manager) predicts how certain data classes will likely be used in the future and/or saves the data items in a manner and/or a location that substantially optimizes utilization of the data items by an instruction group and/or storage of the data items by the computing device. Any suitable type of predictive algorithm providing meaningful results may be used, including a predictive algorithm based on a Bayesian method, and/or a learning algorithm. The prediction may be written to a ghost page associated with a piece of data. A prediction may be straight forward if it is known that the data piece will never be written or read. Each data item will expose what its peculiar flavor is. This may be implemented down to the size of a single cache line, or even below the cache line.
An embodiment provides storage mobility for data items that are associated together in a substantial disequilibrium based upon a shared fate, a shared nature, an entanglement to a page and/or line of similarly handled data. The data item may include one or more extra bits (tag) on end of a data item that may indicate its size, nature (written but never read, read but never written, read once in the life of the program, used by at least two threads). In a further embodiment, an indicator may say which code relates with to the data item. This may be used for doing storage assignment. For example, if the data item includes a semaphore that is used across multiple threads, that should be known and the data item managed accordingly. Most data is associated with a particular body of code and assigned to a storage unit together. By watching that, these assignments can be done together between the I-cache and the D-cache.
The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, flow diagrams, operation diagrams, flowcharts, illustrations, and/or examples. Insofar as such block diagrams, operation diagrams, flowcharts, illustrations, and/or examples contain one or more functions and/or operations, it will be understood by those within the art that each function and/or operation within such block diagrams, operation diagrams, flowcharts, illustrations, or examples can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof.
In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein are capable of being distributed as a program product in a variety of forms, and that an illustrative embodiment of the subject matter described herein applies equally regardless of the particular type of signal bearing media used to actually carry out the distribution. Examples of a signal bearing media include, but are not limited to, the following: recordable type media such as floppy disks, hard disk drives, CD ROMs, digital tape, and computer memory; and transmission type media such as digital and analog communication links using TDM or IP based communication links (e.g., packet links).
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.).
The herein described aspects depict different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected,” or “operably coupled,” to each other to achieve the desired functionality. Any two components capable of being so associated can also be viewed as being “operably couplable” to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components.
While particular aspects of the present subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from this subject matter described herein and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this subject matter described herein. Furthermore, it is to be understood that the invention is defined by the appended claims.

## Claims

1. A device comprising:
a processor;
a hardware resource operatively associated with the processor; and
a resource manager operable to:
compare a first execution of one or more instructions pursuant to an optimistic resource management policy applied to the hardware resource and a second execution of one or more instructions pursuant to a pessimistic resource management policy applied to the hardware resource, the optimistic resource management policy assuming that less than an optimistic level of at least one error will occur during the first execution, and the pessimistic resource management policy assuming that greater than a pessimistic level of the at least one error will occur during the second execution;
based at least partially on the comparison, select a resource management policy from between the optimistic and pessimistic resource management policies; and
associate the selected resource management policy with the one or more instructions.

2. The device of claim 1, wherein at least one of the optimistic resource management policy or the pessimistic resource management policy is based at least partially on at least one of theoretical information or historical information.

3. The device of claim 1, wherein the processor is formed on a first chip and the hardware resource is formed on a second chip.

4. The device of claim 1, wherein at least two of the resource manager, the hardware resource, or the processor are formed on a single chip.

5. The device of claim 1, wherein the hardware resource includes a cache.

6. The device of claim 5, wherein the cache includes at least one of an on-chip cache or an off-chip cache.

7. The device of claim 1, wherein the hardware resource includes a branch predictor.

8. The device of claim 1, wherein the hardware resource operatively associated with the processor includes:
a hardware resource at least one of logically associated with the processor, physically associated with the processor, or managed by the processor.

9. The device of claim 1, wherein the resource manager operable to compare includes:
a resource manager operable to compare according to a preselected criterion.

10. The device of claim 9, wherein the preselected criterion includes:
at least one of a successful completion of the instruction group, an unsuccessful completion of the instruction group, an uncertain completion of the instruction group, an exception, a time to execute the instruction group, a successful hit, an unsuccessful hit, a hit ratio, correctly predicting a branch taken, incorrectly predicting a branch taken, correctly predicting a branch not taken, and/or incorrectly predicting a branch not taken.

11. The device of claim 1, wherein the resource manager operable to select a resource management policy from between the optimistic and pessimistic resource management policies includes:
a resource manager operable to select a resource management policy from between the optimistic and pessimistic resource management policies according to a preselected criterion.

12. The device of claim 11, wherein the preselected criterion includes:
a criterion responsive to an output of the comparison of the first and second executions.

13. The device of claim 11, wherein the preselected criterion includes:
a preselected criterion responsive to at least one of a successful completion of the one or more instructions, an unsuccessful completion of the one or more instructions, an uncertain completion of the one or more instructions, an exception, a time to execute the one or more instructions, a successful hit, an unsuccessful hit, a hit ratio, correctly predicting a branch taken, incorrectly predicting a branch taken, correctly predicting a branch not taken, and/or incorrectly predicting a branch not taken.

14. The device of claim 1, wherein the resource manager operable to select a resource management policy from between the optimistic and pessimistic resource management policies includes:
a resource manager operable to select a resource management policy based on an occurrence rate of the at least one error.

15. The device of claim 1, wherein the resource manager operable to select a resource management policy from between the optimistic and pessimistic resource management policies includes:
a resource manager operable to select a resource management policy predicted as likely to provide a substantially optimum execution of the one or more instructions.

16. The device of claim 1, wherein the resource manager operable to select a resource management policy from between the optimistic and pessimistic resource management policies includes:
a resource manager operable to select a resource management policy predicted by a Bayesian method as likely to provide a substantially optimum execution of the one or more instructions.

17. The device of claim 16, wherein the resource manager operable to select a resource management policy predicted by a Bayesian method as likely to provide a substantially optimum execution of the one or more instructions includes:
a resource manager operable to recall historical data from a ghost page.

18. The device of claim 1, wherein the resource manager operable to select a resource management policy from between the optimistic and pessimistic resource management policies includes:
a resource manager operable to select a management policy predicted by a heuristic as likely to provide a substantially optimum execution of the one or more instructions.

19. The device of claim 1, wherein the resource manager operable to select a resource management policy from between the optimistic and pessimistic resource management policies includes:
a resource manager operable to select a management policy predicted by a learning algorithm as likely to provide a substantially optimum execution of the one or more instructions.

20. The device of claim 1, wherein the resource manager operable to associate the selected resource management policy with the one or more instructions includes:
a resource manager operable to associate a ghost page indicative of the selected resource management policy with the one or more instructions.

21. The device of claim 1, wherein the at least one error includes:
at least one of a hardware error, a fetch error, a memory error, a cache miss, a software error, an arithmetic overflow, a stale datum, a branch prediction error, an attempt to access forbidden memory, and/or an inability of an operating system to grant a request.

22. A method comprising:
applying an optimistic policy to a device having a resource operatively associated with a processor, the optimistic policy assuming that one or more instructions will execute such that less than an optimistic level of at least one error will occur during execution of one or more instructions;
after applying the optimistic policy, executing one or more instructions at least partially using the processor;
applying a pessimistic policy to the device having the resource operatively associated with the processor, the pessimistic policy assuming that the one or more instructions will execute such that greater than a pessimistic level of the at least one error will occur during execution of the one or more instructions;
after applying the pessimistic policy, executing one or more instructions at least partially using the processor;
selecting from the optimistic policy and the pessimistic policy a management policy based at least partially on the executing of the one or more instructions after applying the optimistic policy and the executing of the one or more instructions after applying the pessimistic policy; and
associating the selected management policy with the one or more instructions in a common storage hierarchy.

23. The method of claim 22, wherein at least one of the optimistic policy or the pessimistic policy is based at least partially on at least one of theoretical information or historical information that the one or more instructions will execute in a substantially optimal manner.

24. The method of claim 22, wherein selecting from the optimistic policy and the pessimistic policy a management policy based at least partially on the executing of the one or more instructions after applying the optimistic policy and the executing of the one or more instructions after applying the pessimistic policy includes:
comparing a first execution of the one or more instructions after applying the optimistic policy with a second execution of the one or more instructions after applying the pessimistic policy.

25. The method of claim 22, wherein selecting from the optimistic policy and the pessimistic policy a management policy based at least partially on the executing of the one or more instructions after applying the optimistic policy and the executing of the one or more instructions after applying the pessimistic policy includes:
selecting a management policy likely to provide a substantially optimum execution of the one or more instructions according to a preselected criterion.

26. The method of claim 22, wherein selecting from the optimistic policy and the pessimistic policy a management policy based at least partially on the executing of the one or more instructions after applying the optimistic policy and the executing of the one or more instructions after applying the pessimistic policy includes:
comparing the execution of the one or more instructions pursuant to the optimistic policy and the execution of the one or more instructions pursuant to the pessimistic policy.

27. The method of claim 22, wherein associating the selected management policy with the one or more instructions in a common storage hierarchy includes:
associating the selected management policy with the one or more instructions in a manner useable by a resource manager in conjunction with a subsequent execution of the one or more instructions.

28. The method of claim 22, wherein the associating the selected management policy with the one or more instructions in a common storage hierarchy includes:
associating a ghost page indicative of the selected management policy together with the one or more instructions in the common storage hierarchy.

29. The method of claim 22, further comprising:
storing an indication of the selected management policy likely to provide a substantially optimum execution of the one or more instructions.

30. The method of claim 22, wherein associating the selected management policy with the one or more instructions in a common storage hierarchy includes
saving the selected management policy together with the one or more instructions in the common storage hierarchy.

31. The method of claim 22, further comprising:
saving an indication of the selected management policy likely to provide a substantially optimum execution of the one or more instructions.

32. A device comprising:
means for processing;
resource means operatively associated with the means for processing; and
means for comparing a first execution of one or more instructions pursuant to an optimistic resource management policy applied to the resource means and a second execution of one or more instructions pursuant to a pessimistic resource management policy applied to the resource means, the optimistic resource management policy assuming that the one or more instructions will execute such that less than an optimistic level of at least one error will occur during the first execution, and the pessimistic resource management policy assuming that the one or more instructions will execute such that greater than a pessimistic level of the at least one error will occur during the second execution;
means for selecting a resource management policy from between the optimistic and pessimistic resource management policies based at least partially on the comparison by the means for comparing; and
means for associating the selected resource management policy with the one or more instructions.

33. The device of claim 32, wherein the means for associating the selected management policy together with the one or more instructions includes:
means for storing the selected management policy together with the one or more instructions in a common storage hierarchy.

34. The device of claim 32, wherein the means for associating the selected management policy together with the one or more instructions includes:
means for associating a ghost page indicative of the selected management policy together with the one or more instructions in a common storage hierarchy.