# Patent

## Title
Voltage management of processors in a bladed system based on number of loaded processors

## Abstract

A method includes modulating a first voltage level of a first processor and a second voltage level of a second processor within a processor-based system. The first processor processes applications at a first performance level and the second processor processes applications at a second performance level. The first performance level is higher than said second performance level. A system includes means for modulating a first voltage level of a first processor, which processes applications at a first performance level, and means for modulating a second voltage level of a second processor, which processes applications at a second performance level, with a processor-based system.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to U.S. patent application Ser. No. 10/216,437, entitled “SYSTEM, METHOD AND APPARATUS FOR THE FREQUENCY MANAGEMENT OF BLADES IN A BLADED ARCHITECTURE BASED ON PERFORMANCE REQUIREMENTS” to Andrew H. BARR, et al.; U.S. patent application Ser. No. 10/216,438, entitled “SYSTEM AND METHOD FOR THE FREQUENCY MANAGEMENT OF COMPUTER SYSTEMS TO ALLOW CAPACITY ON DEMAND” to Andrew H. BARR, et al.; U.S. patent application Ser. No. 10/216,283, entitled “SYSTEM, METHOD AND APPARATUS FOR PERFORMANCE OPTIMIZATION AT THE PROCESSOR LEVEL” to Ricardo ESPINOZA-IBARRA, et al.; U.S. patent application Ser. No. 10/216,234, entitled “SYSTEM AND METHOD FOR LOAD DEPENDENT FREQUENCY AND PERFORMANCE MODULATION IN BLADED SYSTEMS” to Ricardo ESPINOZA-IBARRA, et al.; U.S. patent application Ser. No. 10/216,284, entitled “VOLTAGE MANAGEMENT OF BLADES IN A BLADED ARCHITECTURE BASED ON PERFORMANCE REQUIREMENTS” to Andrew H. BARR, et al.; U.S. patent application Ser. No. 10/216,286, entitled “VOLTAGE MODULATION IN CONJUNCTION WITH PERFORMANCE OPTIMIZATION AT PROCESSOR LEVEL” to Andrew H. BARR, et al.; U.S. patent application Ser. No. 10/216,285, entitled “SYSTEM AND METHOD FOR MANAGING THE OPERATING FREQUENCY OF PROCESSORS OR BLADES” to Ricardo ESPINOZA-IBARRA, et al.; U.S. patent application Ser. No. 10/216,229, entitled “SYSTEM AND METHOD FOR MANAGING THE OPERATING FREQUENCY OF BLADES IN A BLADED-SYSTEM” to Ricardo ESPINOZA-IBARRA, et al.; U.S. patent application Ser. No. 10/216,232, entitled “SYSTEM AND METHOD FOR VOLTAGE MANAGEMENT OF A PROCESSOR TO OPTIMIZE PERFORMANCE AND POWER DISSIPATION” to Andrew H. BARR, et al., and U.S. patent application Ser. No. 10/216,435, entitled “MANAGEMENT OF A MEMORY SUBSYSTEM” to Andrew H. BARR, et al., all of which are concurrently herewith being filed under separate covers, the subject matters of which are herein incorporated by reference.
BACKGROUND
Blade servers are computing systems that provision servers or other computer resources on individual cards, or blades. There are many types of blades—server blades, storage blades, network blades, etc. The blades of a server are typically housed together in a single structure, creating high-density systems with a modular architecture that ensures flexibility and scalability. Thus, blade servers reduce space requirements. Server blades, along with storage, networking and other types of blades, are typically installed in a rack-mountable enclosure, or chassis, that hosts multiple blades that share common resources such as cabling, power supplies, and cooling fans.
The telecommunications industry has been using blade server technology for many years. The condensed server bladed architecture also benefits people and businesses that use the Internet to generate revenues and provide services to customers, that are moving some of their business processes to the Web, and that need the flexibility to deploy Internet-edge applications in their own data center. Because of recent developments in technology, blade servers are now used for applications such as web hosting, web caching and content streaming. Web caching, for example, stores frequently requested Web content closer to the user so objects can be retrieved more quickly, thereby reducing the time and the bandwidth required to access the Internet. Companies and individuals are now streaming media, such as video, audio, and interactive, in order to more effectively communicate both internally and externally. This has led to a massive growth of rich media content delivery on the Internet. Bladed servers are being used to meet these new demands.
Bladed servers, however, create challenging engineering problems, due largely in part to heat produced by the blades and limited space in the chassis. Typically, bladed server systems are limited by an underlying power and thermal envelope. For example, a chassis that hosts a bladed system may only be designed to utilize a limited number of watts. That is, the chassis can only can consume so much power and is limited in the amount of airflow that is available to cool the blades in the chassis.
Engineering challenges occur in optimizing the tradeoff between performance and thermal and power requirements. In a bladed architecture multiple blades, each representing a separate system, are present in the same chassis. Associated with the chassis are a specific set of power and thermal requirements. Specifically, these requirements put a limit on the amount of power that can be consumed by the respective blades.
Known power limiting strategies include powering down a CPU functional unit, e.g., a floating-point unit or an on-die cache, or trading off speed for reduced power consumption in a hard drive. Power limitations also put a constraint on the frequency that the processors on the blade can run, and thus, limits the performance. In addition, the processors in a system are usually all configured to operate at the same frequency. This further limits the ability for the individual processors to operate at optimal performance and capacity.
Prior solutions run all the blades at a performance level less than their maximum in order to meet the overall chassis power and thermal cooling budget. A disadvantage associated with this solution is that the performance of each blade is degraded or diminished to fall within these budgets. For example, if the ability of the chassis to cool is limited to X and there are Y blades, each blade can only contribute approximately X/Y to the dissipated power in the chassis. Thus, each blade is limited to the performance associated with an X/Y power level.
Another solution has been to load only one blade or only one type of blade in the system to prevent having to differential between the performance of individual blades in the system. Alternatively, a solution has been to limit the supported combination of blades the system can handle at a time.
Another solution has been to add a plurality of loud, space-consuming fans that require expensive control circuitry. These cooling systems increase the cost of the server blade system, leave less space for other features within the chassis for other features, and run a higher risk for failures and increased downtime. Other solutions have included limiting the number of I/O cards in the blade server system, as well as restricting the number of other use features. A further solution has been to reduce the power budget available for other features in the blade server system.
Other solution have included using expensive infrastructure to ensure optimal ventilation to the system and using expensive infrastructure to ensure optimal power deliver to the system. A further solution has been to ignore system specifications and run the system at a high risk of system failure.
What is needed is a method for modifying the voltage and frequency at which an individual blade operates based on the number of blades, or loads, hosted within the system chassis so that all blades hosted within the chasses operate at optimal performance.
SUMMARY
The method and system described in the present application is advantageous in allowing the voltage and frequency of an individual processor to be modulated in accordance with performance demands of that individual processor, and the overall system power and thermal budget of a multi-processor system.
These and other advantages are found, for example, in a method that includes determining the number of loaded processors within a processor-based system and the optimal performance configuration for each of the individual processors based at least in part on the number of processors loaded in the computer system and the overall thermal and power envelope for the computer system. The method also includes modulating a voltage level of a processor within the processor-based system, the voltage level based on the number of loaded blades.
These and other advantages are also found, for example, in a system that includes means for determining the number of loaded processors within a processor-based system. The system also includes a means for determining an optimal performance configuration for each of the individual processors based at least in part on the number of the loaded processors and the overall thermal and power envelope. The system also includes means for modulating a voltage level of a processor within the system, the voltage level based on the number of loaded processors.
These and other advantages are further found, for example, in a system that includes a number of processors. The system also includes a user interface, which receives an input signal. The input signal comprises instructions for modulating a voltage level of a processor in the number of processors based on the number of loaded processors. The system also includes an Inter-IC bus and an input/output expander, which receives the input signal from the Inter-IC bus and generates a control signal. The control signal comprises information determined by the instructions contained in the input signal. The system further includes a DC-to-DC converter, which generates an output voltage and provides the output voltage to the processor.
These and other advantages are also found in a system that includes a number of processors. The system also includes a serial presence detect circuit, which computes an output voltage of a processor based on the number of loaded processors. The serial presence detect circuit also generates an input signal, which comprises instructions for modulating a voltage level of the processor. The system also includes an Inter-IC bus and an input/output expander, which receives the input signal from the Inter-IC bus and generates a control signal, which comprises information determined by the instructions contained in the input signal. The system further includes a DC-to-DC converter, which generates the output voltage and provides the first output voltage to the processor.
These and other advantages are further found, for example, in a system that includes a number of processors. The system also includes a manual configuration device, which provides an input signal. The input signal comprises instructions for modulating a voltage level of a processor based on the number of loaded processors. The system also includes a DC-to-DC converter, which generates an output voltage based on information contained in the control signal and provides the output voltage to the processor.
These and other advantages are also found, for example, in a system that includes a number of processors. The system also includes a user interface, which receives an input signal. The input signal comprises instructions for modulating a voltage level of a processor in the number of processors based on the number of loaded processors. The system also includes an Inter-IC bus and a microprocessor, which receives the input signal from the Inter-IC bus and generates a control signal. The control signal comprises information determined by the instructions contained in the input signal. The system further includes a DC-to-DC converter, which generates an output voltage based on information contained in the control signal and provides the output voltage to the processor.
These and other advantages are also found, for example, in a system that includes a number of processors. The system also includes a user interface, which receives an input signal. The input signal comprises instructions for modulating a voltage level of a processor in the number of processors based on the number of loaded processors. The system also includes an Inter-IC bus and a microcontroller, which receives the input signal from the Inter-IC bus and generates a control signal. The control signal comprises information determined by the instructions contained in the input signal. The system further includes a DC-to-DC converter, which generates an output voltage based on information contained in the control signal and provides the output voltage to the processor.
These and other advantages are further found, for example, in a system that includes a number of processors. The system also includes a user interface, which receives an input signal. The input signal comprises instructions for modulating a voltage level of a processor in the number of processors based on the number of loaded processors. The system also includes an Inter-IC bus and a field programmable gate array, which receives the input signal from the Inter-IC bus and generates a control signal. The control signal comprises information determined by the instructions contained in the input signal. The system further includes a DC-to-DC converter, which generates an output voltage based on information contained in the control signal and provides the output voltage to the processor.
These and other advantages are also found, for example, in a system that includes a number of processors. The system also includes a user interface, which receives an input signal. The input signal comprises instructions for modulating a voltage level of a processor in the number of processors based on the number of loaded processors. The system also includes an Inter-IC bus and a programmable logic device, which receives the input signal from the Inter-IC bus and generates a control signal. The control signal comprises information determined by the instructions contained in the input signal. The system further includes a DC-to-DC converter, which generates an output voltage based on information contained in the control signal and provides the output voltage to the processor.



DESCRIPTION OF THE DRAWINGS
The detailed description will refer to the following drawings, wherein like numerals refer to like elements, and wherein:
FIG. 1 shows a block diagram depicting one embodiment of the basic modular building blocks of a bladed architecture system;
FIG. 2 illustrates a block diagram depicting one methodology of managing the operating voltage of individual processors by use of an input/output expander chip;
FIG. 3 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual processors by use of a manual configuration device;
FIG. 4 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual processors by use of a microcontroller or microprocessor;
FIG. 5 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual processors by use of a field programmable gate array or programmable logic device;
FIG. 6 illustrates a block diagram depicting a series of processors inside of a bladed architecture chassis; and
FIG. 7 illustrates a block diagram depicting a series of blades inside of a bladed architecture chassis running at modified voltages.



DETAILED DESCRIPTION
The preferred embodiments of the method for voltage management of processors in a bladed system based on loading will now be described in detail with reference to the following figures, in which like numerals refer to like elements. FIG. 1 illustrates a block diagram depicting one embodiment of the basic modular building blocks of a bladed architecture system, generally designated by the reference numeral 100. Blades within bladed architecture system 100 host processors that run various applications. The management processor 110 supervises the functions of the chassis and provides a single interface to the consoles of all the servers installed. As shown FIG. 1, the server processors 120 are in communication with the management processor 110. The server processors 120 are, in turn, in communication with other processors that perform specific functions. For example, as seen in the FIGURE, server processors 120 are in communication with fiber channel processors 130 and network processors 140. It is to be appreciated that the various processors in a bladed architecture system 100 may be server processors, network processors, storage processors or storage interconnect processors, etc. In general, blade servers of the same type (server, fibre channel, network, etc.) contain the same hardware and software components, although the different blade servers may be running at a different voltage or frequency than other blade servers of the same type.
By taking advantage of a processor's process requirements for higher or lower performance, each processor is allowed to run at an increased/decreased frequency and thus consume more or less of the chassis thermal and power budget. Management processors 110 that run processes that require a higher level of performance are run at a higher frequency and thus consume more of the chassis's thermal and power budget. Slave processors 120 that run background processes that require a lower level of performance are run at a lower frequency and thus consume less of the chassis's thermal and power budget. In either scenario, the overall thermal and power requirements of bladed architecture system 100 are still met with a more optimal overall processor performance.
As discussed above, it is desirous to create a bladed architecture system 100 in which it is possible to adjust the voltage of the processors 110, 120, 130, 140 individually. In one embodiment, the voltage and the frequency of a particular processor, or blade hosting that processor, are adjusted simultaneously. One skilled in the art will appreciate that techniques described herein for modifying the voltage of a processor can also be used to modify the voltage used by a blade hosting that processor. In general, as the voltage of a processor is increased (within a specific range) the frequency at which the processor can run also increases. Conversely, as the voltage of the processor is decreased, the frequency at which the processor can run decreases. Thus, when the frequency of the processor is decreased because a lower level of performance is required, the voltage may also be decreased with the frequency, providing a large thermal and power relief Because the power dissipated by the processor is proportional to the frequency and square of the voltage, modulating the voltage provides a large additional benefit over just modulating the frequency.
In many bladed architecture systems 100 the voltage that a processor or memory runs off of is generated by a voltage converter called a DC-to-DC converter. The DC-to-DC converter takes in some a global system power that operates all servers within a chassis, for example five volts, and from that global system power generates the specific voltage requirement for the individual processors 110, 120, 130, 140 hosted within the chassis. The DC-to-DC converter is typically controlled using an ASIC as the central controller within a circuit. The modulation of the voltage to processors 110, 120, 130, 140 can be accomplished by providing a serial or parallel digital input to “trim” pins on the DC-to-DC converter. By making small changes in a value at a given trim pin in the DC-to-DC converter circuit, the output voltage can be slightly increased or decreased. For example, two volts can be changed to 2.1, 2.2 volts, etc. FIGS. 2–5 illustrate different methodologies of the how the input to the trim pins of the DC-to-DC converter can be controlled. One of ordinary skill in the art would readily recognize that the principles disclosed herein may be applied to a variety of processor architectures, including PA-RISC, DEC Alpha, MIPS, PowerPC, SPARC, IA-32 and IA-64.
FIG. 2 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual processors, or blades hosting that processor, by use of an Inter-IC (I2C) device, such as an Input/Output (I/O) expander chip, generally designated by the reference numeral 200. I2C method 200 includes: providing a control signal from I2C bus 210; providing the control signal to an I/O expander chip 220; generating a “trim in” signal 230; providing a “voltage in” signal 240; providing the “voltage in” signal 240 to trim pins of a DC-to-DC converter 250; and generating an output voltage 260.
An I2C bus 210, or other control bus, is used to control I/O expander chip 220. As is known to those skilled in the art, I2C bus 210 is a bi-directional two-wire serial bus that provides a communication link between integrated circuits. In one embodiment, where processors 110, 120, 130, 140 are a PA-RISC processor, control signals are provided to I2C bus 210 manually using a Guardian Service Processor (GSP) console. GSP is a management consol that allows user control of various parameters of bladed architecture system 100, for example, the voltage being provided to a particular processor 110, 120, 130, 140 or processor hosted within bladed architecture system 100. The user-friendly interface of the GSP console allows the user to manually control the voltage of the processors 110, 120, 130, 140 within bladed architecture system 100 without requiring knowledge of any low-level information, such as bit-settings.
In another embodiment, control signals are provided to I2C bus 210 automatically using serial presence detect (SPD) functionality. SPD is a serial bus that queries different parts of bladed architecture system 100 to determine the loading status of optionally loaded features. These optionally loaded features include, for example, processors 110, 120, 130, 140 or any other board. Bladed architecture system 100 can automatically detect the appropriate voltage for each processor 110, 120, 130, 140 that would maximize the performance of that processor 110, 120, 130, 140 within the thermal and power limits of bladed architecture system 100. SPD utilizes I2C bus 210 to query all processors 110, 120, 130, 140 in bladed architecture system 100 to determine how many processors are loaded with the chassis of bladed architecture system 100, to determine the performance requirement for the processors 110, 120, 130, 140, etc. The information is then used to automatically modulate the voltage provided to processors 110, 120, 130, 140.
I/O expander chip 220 can be an inexpensive serial-to-parallel type of chip that is controlled using I2C bus 210. I/O expander chip 220 has input/output (I/O) ports that are forced to a particular state by writing to I/O expander chip 220 through an I2C command. Since I/O expander chip 220 is I2C based, I/O expander chip 220 can be controlled by any device that supports an I2C interface, such as a GSP or SPD, as described previously. I/O expander chip 220 typically has multiple I/O ports. Therefore, one I/O expander chip 220 can be used to control multiple DC-to-DC converters 250 individually. I/O expander chip 220 generates “trim in” signal 230, an N bits wide control signal that is input to the trim pins of DC-to-DC converter 250. The “trim in” signal 230 contains information regarding voltage modulation from the user. The “trim in” signal 230 is provided to DC-to-DC converter 250 to provide an appropriate input into the trim pins of DC-to-DC converter 250 to control the voltage of the processors 110, 120, 130, 140. The “voltage in” signal 240 is also provided to DC-to-DC converter 250 in order to provide a reference voltage level against which the processor voltage is compared. The reference voltage level represents the global system power of bladed architecture systems 100, the maximum voltage accessible by any one processor 110, 120, 130, 140 hosted within bladed architecture system 100. DC-to-DC converter 250 then generates the appropriate output voltage 260 for the processors 110, 120, 130, 140 to optimize performance of the processors 110, 120, 130, 140 within the thermal and power limitations of the bladed architecture system 100. The output voltage 260 is applied to the various processors 110, 120, 130, 140 using the trim pins on DC-to-DC converter 250.
FIG. 3 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual processors, or blades hosting that processor, by use of a manual configuration device, generally designated by the reference numeral 300. Manual configuration device method 300 includes: setting manual configuration device 310 on the bladed architecture system 100, generating a “trim in” signal 320; providing a “voltage in” signal 330; providing the “voltage in” signal 330 to trim pins of a DC-to-DC converter 340; and generating an output voltage 350.
One of ordinary skill in the art would recognize that there are many common manual configuration devices that are capable of performing the desired function, e.g., dip switches, jumpers installed over pin headers, rotational configuration switches, and solder bridges, etc. For example, in one embodiment, dip switches may be used as the manual configuration device 310. As known in the art, dip switches 310 are a series of tiny switches built into circuit boards, for example, the circuit boards that comprise the processors 110, 120, 130, 140.
Manual configuration device 310 enables the user to configure the processors. In the present embodiment, the manual configuration device 310 allow the user to modulate the voltage being used by a particular processor 110, 120, 130, 140. Manual configuration devices are typically toggle switches and have two possible positions—on or off (or bit positions 0 and 1). The manual configuration device 310 is added to a physically readily accessible part of bladed architecture system 100, such as on an exterior portion of bladed architecture system 100. Thus, the user, or operator, is allowed to manually set the voltage of the processors 110, 120, 130, 140 upon reboot of the bladed architecture system 100, based on predetermined performance requirements. However, the user is required to know the appropriate settings of the configuration bits of the trim pins of DC-to-DC converter 450.
Manual configuration device 310 generates “trim in” signal 320, an N bits wide control signal that is input to the trim pins of DC-to-DC converter 340. The “trim in” signal 320 contains information regarding voltage modulation from the user. The “trim in” signal 320 is provided to DC-to-DC converter 340 to provide an appropriate input into the trim pins of DC-to-DC converter 340 to control the voltage of the processors 110, 120, 130, 140. The “voltage in” signal 330 is also provided to DC-to-DC converter 340 in order to provide a reference voltage level against which the processor voltage is compared. The reference voltage level represents the global system power of bladed architecture systems 100, the maximum voltage accessible by any one processor 110, 120, 130, 140 hosted within bladed architecture system 100. DC-to-DC converter 340 then generates the appropriate output voltage 350 for the processors 110, 120, 130, 140 to optimize performance of the processors 110, 120, 130, 140 within the thermal and power limitations of the bladed architecture system 100. The output voltage 350 is applied to the various processors 110, 120, 130, 140 using the trim pins of DC-to-DC converter 340.
FIG. 4 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual processors, or blades hosting that processor, by use of a microprocessor/microcontroller, generally designated by the reference numeral 400. Microprocessor method 400 includes: providing a control signal from I2C bus 410; providing the control signal to a microprocessor/microcontroller 420; generating a “trim in” signal 430; providing a “voltage in” signal 440; providing the “voltage in” signal 440 to trim pins of a DC-to-DC converter 450; and generating an output voltage 460.
An I2C bus 410 is used to control microprocessor/microcontroller 420. As is known in the art, I2C bus 410 is a bi-directional two-wire serial bus that provides a communication link between integrated circuits. Microprocessor/microcontroller 420 is interfaced with the user using I2C bus 410 to allow the user to input the voltage at which the user wants to run the processors 110, 120, 130, 140. User input can be accomplished using a higher-level interface device, for example, a console. Microprocessor/microcontroller 420 can be programmed to automatically convert the user input into the appropriate commands to modulate the voltage of the processors 110, 120, 130, 140 without requiring the user to know the appropriate settings of the configuration bits of the trim pins of DC-to-DC converter 450.
Microprocessor/microcontroller 420 generates “trim in” signal 430, an N bits wide control signal that is input to the trim pins of DC-to-DC converter 450. The “trim in” signal 430 contains information regarding voltage modulation from the user. The “trim in” signal 430 is provided to DC-to-DC converter 450 to provide an appropriate input into the trim pins of DC-to-DC converter 450 to control the voltage of the processors 110, 120, 130, 140. The “voltage in” signal 440 is also provided to DC-to-DC converter 450 in order to provide a reference voltage level against which the processor voltage is compared. The reference voltage level represents the global system power of bladed architecture systems 100, the maximum voltage accessible by any one processor 110, 120, 130, 140 hosted within bladed architecture system 100. DC-to-DC converter 450 then generates the appropriate output voltage 460 for the processors 110, 120, 130, 140 to optimize performance of the processors 110, 120, 130, 140 within the thermal and power limitations of the bladed architecture system 100. The output voltage 460 is applied to the various processors 110, 120, 130, 140 using the trim pins of DC-to-DC converter 450.
FIG. 5 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual processors, or blades hosting that processor, by use of a field-programmable gate array (FPGA) or programmable logic device (PLD), generally designated by the reference numeral 500. FPGA/PLD method 500 includes: providing a control signal from I2C bus 510; providing the control signal to an FPGA/PLD 520; generating a “Trim in” signal 530; providing a “voltage in” signal 540; providing the “voltage in” signal 540 to trim pins of a DC-to-DC converter 550; and generating an output voltage 560.
An I2C bus 510 is used to control FPGA/PLD 520. As is known in the art, I2C bus 510 is a bi-directional two-wire serial bus that provides a communication link between integrated circuits. A FPGA is a chip is a particular type of PLD that can be programmed in the field after manufacture. The FPGA/PLD 520 is interfaced with the user using I2C bus 410 to allow the user to input the voltage at which the user wants to run the processors 110, 120, 130, 140. User input can be accomplished using a higher-level interface device, for example, a console. Like the use of microcontroller/microprocessor 420 described with reference to FIG. 5, FPGA/PLD 520 allows the user to control the voltage modulation in a more transparent way, i.e., the user is not required to know the appropriate settings of the configuration bits of the trim pins of DC-to-DC converter 550.
FPGA/PLD 520 generates “trim in” signal 530, an N bits wide control signal that is input to the trim pins of DC-to-DC converter 550. The “trim in” signal 530 contains information regarding voltage modulation from the user. The “trim in” signal 530 is provided to DC-to-DC converter 550 to provide an appropriate input into the trim pins of DC-to-DC converter 550 to control the voltage of the processors 110, 120, 130, 140. The “voltage in” signal 540 is also provided to DC-to-DC converter 550 in order to provide a reference voltage level against which the processor voltage is compared. The reference voltage level represents the global system power of bladed architecture systems 100, the maximum voltage accessible by any one processor 110, 120, 130, 140 hosted within bladed architecture system 100. DC-to-DC converter 550 then generates the appropriate output voltage 560 for the processors 110, 120, 130, 140 to optimize performance of the processors 110, 120, 130, 140 within the thermal and power limitations of the bladed architecture system 100. The output voltage 560 is applied to the various processors 110, 120, 130, 140 using the trim pins of DC-to-DC converter 550.
FIG. 6 illustrates a block diagram depicting a series of processors inside of the chassis of bladed architecture system 100 running at the same voltage, generally designated by the reference numeral 600. The shading of the individual processors indicates that each individual processor is operating at the same voltage level. Operating processors at the same voltage is typical in current bladed architecture system. In addition, the shading illustrates that each processor is operating at below a maximum performance level of that processor in order to remain under the maximum power allocated to the system as a whole. Conversely, each processor could also run at the maximum performance level for that process, thus taxing the power and thermal allotment of bladed architecture system 100. As discussed previously, bladed server systems are limited by an underlying power and thermal envelope. This is due to the heat produced within the processors and to the limited dimensions in the chassis. When the chassis consumes a given amount of the power, the chassis is typically limited in the amount of airflow that is available to cool the processors. As a result, the power limitation limits the voltage that the processors on the processor can run, and thus, limits the performance. Thus, the processors are limited in their ability to operate at optimal performance and capacity, depending on the processes they need to execute, because the processors are configured to operate at the same voltage—a voltage below their maximum level.
FIG. 7 illustrates a block diagram depicting a series of processors inside of a bladed architecture chassis running at modified voltages, generally designated by the reference numeral 700. The system FIG. 7 represents a system where the user has been able to manually or automatically adjust the voltage levels of the various processors or processors in the chassis using at least one of the various methods described previously. As a result, the overall system runs at a much more efficient level. As seen in the FIGURE, each processor is now only using the requisite voltage level that is required for its particular function within the system as limited by the total number of blades loaded in bladed architecture system 100 at that time. Because of the varying levels of voltage available to the individual processors, processors that require a higher voltage than the average can now operate at a more optimum level. Similarly, processors that require less power no longer require to be run at the same voltage level as the other processors. As a result, a more efficient system is created.
If blades are subsequently removed from bladed architecture system 100, the voltage and frequency levels of the processors can be increased since more of the overall power and thermal allotment will be available for the remaining processors. Likewise, if more blades are subsequently added to bladed architecture system 100, the voltage and frequency levels of the processors can be decreased to accommodate the reduced availability of the overall power and thermal allotment for the larger number of processors.
It is to be appreciated that the principles disclosed herein may be applied to a system comprised of blades or processors that share a common chassis or to an architecture system that spans multiple chassis. That is, the principles may be applied to systems that are divided by either a physical or logical partition. For example, physically, a system may include three chassis, with each chassis having eight processors. Logically, the same system could be partitioned into five different web servers for five different customers. Power constraints within a chassis typically concern the physical partition of the system. Power constraints imposed on a customer or application that is located in multiple chassis, typically concern logical partitions. One of ordinary skill in the art would readily recognize that the innovations described above may be applied to both physically and logically partitioned architectures.
While the methods for manually managing the operating voltage of individual blades, or processors, in a blade-based computer system have been described in connection with an exemplary embodiment, those skilled in the art will understand that many modifications in light of these teaching are possible, and this application is intended to cover any variation thereof.
For example, the disclosed system and method makes use of specific I2C devices that are used to receive signals from an I2C bus. Other I2C devices could likewise be used. Thus, the I2C devices shown and referenced generally throughout this disclosure, and unless specifically noted, are intended to represent any and all devices/technologies appropriate to perform the desired function. Likewise, there are disclosed several processors and blades that perform various operations. The specific processor or blade is not important to the system and method described herein. Thus, it is not Applicant's intention to limit the system and method described herein to any particular form of processor, blade or specific blade architecture.
Further examples exist throughout the disclosure, and it is not Applicants' intention to exclude from the scope of this disclosure the use of structures, materials, or acts that are not expressly identified in the specification, but nonetheless are capable of performing a claimed function.

## Claims

1. A method for managing the voltage level of processors in a computer system based on loading, said method comprising the steps of:
identifying the number of loaded processors in said computer system;
determining an optimal performance configuration for each of the individual processors based at least in part on the number of processors loaded in said computer system and the overall thermal and power envelope for said computer system; and
modulating a first voltage level for a first processor from the loaded processors in said computer system, wherein said first voltage level is increased based on an increased performance demand on the first processor; and
modulating a second voltage level for a second processor from the loaded processors in said computer system, wherein said second voltage level is decreased based on a decreased performance demand on the second processor; wherein the loaded processors are optimized to utilize a total voltage allowance of said computer system and said total voltage allowance is determined by an overall thermal and power budget allocation of said computer system, and wherein the first voltage level and the second voltage level comprise said total voltage allowance of said computer system and the increase in the first voltage level and the decrease in the second voltage level occur simultaneously.

2. The method according to claim 1, wherein said voltage level is a fraction of said total voltage allowance of said computer system and wherein said total voltage allowance is determined by overall thermal and power budget allocation of said computer system.

3. The method according to claim 1, further comprising steps of modulating a frequency level of at least one of said processors, said frequency level allowing the processor to process at a performance level.

4. The method according to claim 3, wherein said modulation of said voltage and said modulation of said frequency occur simultaneously.

5. The method according to claim 1, wherein said computer system is based on an architecture chosen from the group consisting of: PA-RISC, IA-32 and IA-64.

6. The method according to claim 5, wherein said computer system is physically partitioned.

7. The method according to claim 5, wherein said computer system is logically partitioned.

8. A system for managing the voltage level of processors in a computer system based on loading comprising:
a set of processors in a chassis in said computer system;
a means for determining the number of loaded processors in said chassis of said computer system;
a means for determining an optimal performance configuration for each of the individual processors based at least in part on the number of processors loaded in said chassis and the overall thermal and power envelope for said computer system; and
a means for setting an individual voltage level for at least one individual processor in said computer system based on said optimal performance configuration, wherein the loaded processors are optimized to utilize a total voltage allowance of said computer system and said total voltage allowance is determined by an overall thermal and power budget allocation of said computer system, and wherein a first voltage level of a first processor in said computer system and a second voltage level of a second processor in said computer system comprise said total voltage allowance of said computer system and wherein the means for setting the individual voltage level increases the first voltage level and decreases the second voltage level simultaneously based on said optimal performance configuration.

9. The system according to claim 8, wherein said voltage level is a fraction of said total voltage allowance of said computer system and wherein the total voltage allowance is determined by said overall thermal and power budget allocation of said computer system.

10. The system according to claim 8, further comprising means for modulating a frequency level of at least one processor, said frequency level allowing the processor to process at a performance level.

11. The system according to claim 10, wherein said modulation of said voltage and said modulation of said frequency occur simultaneously.

12. The system according to claim 8, wherein said computer system is based on an architecture chosen from the group consisting of: PA-RISC IA-32 and IA-64.

13. The system according to claim 8, wherein said computer system is physically partitioned.

14. The system according to claim 8, wherein said computer system is logically partitioned.

15. A system for managing the voltage level of processors in a computer system based on loading comprising:
a set of processors in a chassis in said computer system;
an input selected from the group consisting of (1) a user interface, said user interface receiving an input signal, wherein said input signal comprises instructions for modulating a voltage level of a processor in said computer system based on the number of processors loaded in said computer system, and (2) a serial presence detect circuit, said serial presence detect circuit computing an output voltage of a processor in said computer system based on the number of processors loaded in said computer system and generating an input signal, wherein said input signal comprises instructions for modulating a voltage level of at least one processor in said set of processors; an Inter-IC bus;
an input/output expander, said input/output expander receiving said input signal from said Inter-IC bus and generating a control signal, wherein said control signal comprises information determined by said instructions contained in said input signal; and
a DC-to-DC converter, said DC-to-DC converter generating an output voltage and providing said output voltage to at least one processor in said set of processors, said output voltage based on information contained in said control signal, wherein the loaded processors are optimized to utilize a total voltage allowance of said computer system and said total voltage allowance is determined by an overall thermal and power budget allocation of said computer system, and wherein a first voltage level of a first processor in said computer system and a second voltage level of a second processor in said computer system comprise said total voltage allowance of said computer system, and the the first voltage level increases and the second voltage level decreases simultaneously.

16. A system for managing the voltage level of processors in a computer system based on loading comprising:
a set of processors in a chassis in said computer system;
a manual configuration device, said manual configuration device providing an input signal, wherein said input signal comprises instructions for modulating a voltage level of at least one processor in said set of processors based on the number of loaded processors; and
a DC-to-DC converter, said DC-to-DC converter generating an output voltage and providing said output voltage to said at least one processor in said set of processors, said output voltage based on information contained in said control signal, wherein the loaded processors are optimized to utilize a total voltage allowance of said computer system and said total voltage allowance is determined by an overall thermal and power budget allocation of said computer system, and wherein a first voltage level of a first processor in said computer system and a second voltage level of a second processor in said computer system comprise said total voltage allowance of said computer system, and the the first voltage level increases and the second voltage level decreases simultaneously.

17. A system for managing the voltage level of processors in a computer system based on loading comprising:
a set of processors in a chassis in said computer system; a user interface, said user interface receiving an input signal, wherein said input signal comprises instructions for modulating a voltage level of at least one processor in said set of processors based on the number of loaded processors; an Inter-IC bus;
a signal generator selected from the group consisting of (1) a microprocessor, said microprocessor receiving said input signal from said Inter-IC bus and generating a control signal, wherein said control signal comprises information determined by said instructions contained in said input signal, (2) a microcontroller, said microcontroller receiving said input signal from said Inter-IC bus and generating a control signal, wherein said control signal comprises information determined by said instructions contained in said input signal, (3) a field programmable gate array, said field programmable gate array receiving said input signal from said Inter-IC bus and generating a control signal, wherein said control signal comprises information determined by said instructions contained in said input signal, and (4) a programmable logic device, said programmable logic device receiving said input signal from said Inter-IC bus and generating a control signal, wherein said control signal comprises information determined by said instructions contained in said input signal; and
a DC-to-DC converter, said DC-to-DC converter generating an output voltage and providing said output voltage to said at least one processor in said set of processors, said output voltage based on information contained in said control signal, wherein the optimal performance configuration for each of the individual processors is based at least in part on the number of processors loaded in said chassis and the overall thermal and power envelope for said computer system, and wherein a first voltage level of a first processor in said computer system and a second voltage level of a second processor in said computer system comprise said total voltage allowance of said computer system, and the the first voltage level increases and the second voltage level decreases simultaneously.

18. The method of claim 1, wherein the overall thermal budget is based on heat produced by the loaded processors, dimensions of a chassis in which the loaded processors are installed and an amount of airflow available to cool the loaded processors.

19. The method of claim 1, wherein voltage levels associated with one or more loaded processors are modulated to optimize an overall performance level of the computer system.