Abstract:
A method includes receiving an input signal, which contains instructions for modulating a voltage of a blade, generating a control signal, which is determined by the instructions contained in the input signal, generating an output voltage, and providing the output voltage to the blade. A system includes receiving means for receiving an input signal, first generating means for generating a control signal, second generating means for generating an output voltage, and first providing means for providing the output voltage to the blade.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is related to U.S. patent application Ser. No.10/___,___ (Attorney Docket No. 100202606-1), 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/___,___ (Attorney Docket No. 100202607-1-1), 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/___,___ (Attorney Docket No. 100202610-1), 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/___,___ (Attorney Docket No. 100202612-1), 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/___,___ (Attorney Docket No. 100202878-1), 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/___,___ (Attorney Docket No. 100202880-1), entitled “VOLTAGE MODULATION IN CONJUNCTION WITH PERFORMANCE OPTIMIZATION AT PROCESSOR LEVEL” to Andrew H. BARR, et al.; U.S. patent application Ser. No.10/___,___ (Attorney Docket No. 100202881-1), 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/___,___ (Attorney Docket No. 100202882-1), 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/___,___ (Attorney Docket No. 100202916-1), entitled “VOLTAGE MANAGEMENT OF PROCESSORS IN A BLADED SYSTEM BASED ON LOADING” to Andrew H. BARR, et al., and U.S. patent application Ser. No.10/___,___ (Attorney Docket No. 100203638-1), 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  
         [0002]    Bladed 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, processor 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, bladed 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.  
           [0003]    The telecommunications industry has been using bladed 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, bladed 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.  
           [0004]    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.  
           [0005]    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.  
           [0006]    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.  
           [0007]    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.  
           [0008]    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 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 system.  
           [0009]    What is needed is a method for modulating the frequency and voltage of a blade in a bladed architecture system in accordance with the performance demands of the individual blade and the overall system power and thermal budget of the system.  
         SUMMARY  
         [0010]    The method and system of the present application are advantageous in providing means to change a voltage of a processor in a multi-processor system or a bladed architecture based on performance requirement of the processor.  
           [0011]    These and other advantages are found, for example, in a method that includes receiving an input signal. The input signal contains instructions for modulating a voltage of a blade. The method also includes generating a control signal. The information contained in the control signal is determined by the instructions contained in the input signal. The method further includes generating an output voltage based on the control signal and providing the output voltage to the blade.  
           [0012]    These and other advantages are also found, for example, in a system that includes receiving means for receiving an input signal. The input signal comprises instructions for modulating a voltage of a blade. The system also includes first generating means for generating a control signal. The control contains information determined by the instructions contained in the input signal. The system further includes second generating means for generating an output voltage based on the control signal. The system also includes first providing means for providing the output voltage to the blade.  
           [0013]    These and other advantages are further found, for example, in a system that includes a user interface, which receives an input signal. The input signal comprises instructions for modulating a voltage of a blade and is defined by a user. 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. They 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 blade.  
           [0014]    These and other advantages are also found, for example, in a system that includes a serial presence detect circuit, which computes an output voltage based on an optimal performance level of a blade and generates an input signal. The input signal comprises instructions for modulating a voltage of a blade. 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 the output voltage based on information contained in the control signal and provides the output voltage to the blade.  
           [0015]    These and other advantages are further found, for example, in a system that includes a manual configuration device, which provides an input signal. The input signal comprises instructions for modulating a voltage of a blade and is defined by a user. The manual configuration device also generates a control signal. The control signal comprises information determined by the instructions contained in the input signal. 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 blade.  
           [0016]    These and other advantages are also found, for example, in a system that includes a user interface, which receives an input signal. The input signal comprises instructions for modulating a voltage of a blade and is defined by a user. 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 blade.  
           [0017]    These and other advantages are further found, for example, in a system that includes a user interface, which receives an input signal. The input signal comprises instructions for modulating a voltage of a blade and is defined by a user. 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 blade.  
           [0018]    These and other advantages are also found, for example, in a system that includes a user interface, which receives an input signal. The input signal comprises instructions for modulating a voltage of a blade and is defined by a user. 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 blade.  
           [0019]    These and other advantages are further found, for example, in a system that includes a user interface, which receives an input signal. The input signal comprises instructions for modulating a voltage of a blade and is defined by a user. 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 blade.  
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0020]    The detailed description will refer to the following drawings, wherein like numerals refer to like elements, and wherein:  
         [0021]    [0021]FIG. 1 shows a block diagram depicting one embodiment of the basic modular building blocks of a bladed architecture system;  
         [0022]    [0022]FIG. 2 illustrates a block diagram depicting one methodology of managing the operating voltage of individual blades by use of an input/output expander chip;  
         [0023]    [0023]FIG. 3 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual blades by use of a manual configuration device;  
         [0024]    [0024]FIG. 4 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual blades by use of a microcontroller or microprocessor;  
         [0025]    [0025]FIG. 5 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual blades by use of a field programmable gate array or programmable logic device;  
         [0026]    [0026]FIG. 6 illustrates a block diagram depicting a series of blades inside of a bladed architecture chassis; and  
         [0027]    [0027]FIG. 7 illustrates a block diagram depicting a series of blades inside of a bladed architecture chassis running at different voltages. 
     
    
     DETAILED DESCRIPTION  
       [0028]    The preferred embodiments of the system and method for voltage management of a processor to optimize performance and power dissipation 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, as generally designated by the reference numeral  100 . A management blade  110  supervises the functions of the chassis and provides a single interface to the consoles of all the servers installed. As shown in FIG. 1, server blades  120  are in communication with the management blade  110 . The server blades  120  are, in turn, in communication with other blades that perform specific functions. For example, as seen in the FIGURE, server blades  120  are in communication with fiber channel blades  130  and network blades  140 . It is to be appreciated that the various blades in a bladed architecture system  100  may be server blades, network blades, storage blades or storage interconnect blades, etc. In general, blades of the same type (server, fibre channel, network, etc.) contain the same hardware and software components, although the different blades may be running at a different voltage or frequency than other blades of the same type.  
         [0029]    By taking advantage of a blade&#39;s application requirements for higher or lower performance, each blade is allowed to run at an increased/decreased voltage and frequency and thus consume more or less of the chassis thermal and power budget. Management blades  110  that run processes that require a higher level of performance are run at a higher voltage and frequency and thus consume more of the chassis&#39;s thermal and power budget. Slave blades  120  that run background processes that require a lower level of performance are run at a lower voltage and frequency and thus consume less of the chassis&#39;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 blade performance.  
         [0030]    As discussed above, it is desirous to create a bladed architecture system  100  in which it is possible to adjust the voltage of the blades  110 ,  120 ,  130 ,  140  individually. In one embodiment, the voltage and the frequency of a particular blade, or processor within that blade, 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 the blade in which that processor is hosted. 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 in a blade 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 in a blade is proportional to the frequency and square of the voltage, modulating the voltage provides a large additional benefit over just modulating the frequency.  
         [0031]    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 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 blades  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 blades  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.  
         [0032]    [0032]FIG. 2 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual blades, or processors within that blade, by use of an Inter-IC (I 2 C) device, such as an Input/Output (I/O) expander chip, as generally designated by the reference numeral  200 . I 2 C method  200  includes: providing a control signal from I 2 C 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 .  
         [0033]    An I 2 C bus  210 , or other control bus, is used to control I/O expander chip  220 . As is known to those skilled in the art, I 2 C bus  210  is a bi-directional two-wire serial bus that provides a communication link between integrated circuits. In one embodiment, where blades  110 ,  120 ,  130 ,  140  are a PA-RISC blade, control signals are provided to I 2 C bus  210  manually using a Guardian Service Processor (GSP) console. GSP is a management consol allows user control of various parameters of bladed architecture system  100 , for example, the voltage being provided to a particular blade  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 blades  110 ,  120 ,  130 ,  140  within bladed architecture system  100  without requiring knowledge of any low-level information, such as bit-settings.  
         [0034]    In another embodiment, control signals are provided to I 2 C 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, blades  110 ,  120 ,  130 ,  140  or any other board. Bladed architecture system  100  can automatically detect the appropriate voltage for each blade  110 ,  120 ,  130 ,  140  that would maximize the performance of that blade  110 ,  120 ,  130 ,  140  within the thermal and power limits of bladed architecture system  100 . SPD utilizes I 2 C bus  210  to query all blades  110 ,  120 ,  130 ,  140  in bladed architecture system  100  to determine how many blades are loaded with the chassis of bladed architecture system  100 , to determine the performance requirement for the blades  110 ,  120 ,  130 ,  140 , etc. The information is then used to automatically modulate the voltage provided to blades  110 ,  120 ,  130 ,  140 .  
         [0035]    I/O expander chip  220  can be an inexpensive serial-to-parallel type of chip that is controlled using I 2 C 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 I 2 C command. Since I/O expander chip  220  is I 2 C based, I/O expander chip  220  can be controlled by any device that supports an I 2 C 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 blades  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 blade voltage is compared. The reference voltage level represents the global system power of bladed architecture systems  100 , the maximum voltage accessible by any one blade  110 ,  120 ,  130 ,  140  hosted within bladed architecture system  100 . DC-to-DC converter  250  then generates the appropriate output voltage  260  for the blades  110 ,  120 ,  130 ,  140  to optimize performance of the blades  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 blades  110 ,  120 ,  130 ,  140  using the trim pins on DC-to-DC converter  250 .  
         [0036]    [0036]FIG. 3 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual blades, or processors within that blade, by use of a manual configuration device, as 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 .  
         [0037]    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 are a series of tiny switches built into circuit boards, for example, the circuit boards that comprise the blades  110 ,  120 ,  130 ,  140 .  
         [0038]    Manual configuration device  310  enables the user to configure the blades. In the present embodiment, the manual configuration device  310  allows the user to modulate the voltage being used by a particular blade  110 ,  120 ,  130 ,  140 . The manual configuration device  310  may be 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 blades  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 .  
         [0039]    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 blades  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 blade voltage is compared. The reference voltage level represents the global system power of bladed architecture systems  100 , the maximum voltage accessible by any one blade  110 ,  120 ,  130 ,  140  hosted within bladed architecture system  100 . DC-to-DC converter  340  then generates the appropriate output voltage  350  for the blades  110 ,  120 ,  130 ,  140  to optimize performance of the blades  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 blades  110 ,  120 ,  130 ,  140  using the trim pins of DC-to-DC converter  340 .  
         [0040]    [0040]FIG. 4 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual blades, or processors within that blade, by use of a microprocessor/microcontroller, as generally designated by the reference numeral  400 . Microprocessor method  400  includes: providing a control signal from I 2 C 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 .  
         [0041]    An I 2 C bus  410  is used to control microprocessor/microcontroller  420 . As is known in the art, I 2 C 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 I 2 C bus  410  to allow the user to input the voltage at which the user wants to run the blades  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 blades  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 .  
         [0042]    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 blades  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 blade voltage is compared. The reference voltage level represents the global system power of bladed architecture systems  100 , the maximum voltage accessible by any one blade  110 ,  120 ,  130 ,  140  hosted within bladed architecture system  100 . DC-to-DC converter  450  then generates the appropriate output voltage  460  for the blades  110 ,  120 ,  130 ,  140  to optimize performance of the blades  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 blades  110 ,  120 ,  130 ,  140  using the trim pins of DC-to-DC converter  450 .  
         [0043]    [0043]FIG. 5 illustrates a block diagram depicting an embodiment of a method of managing the operating voltage of individual blades, or processors within that blade, by use of a field-programmable gate array (FPGA) or programmable logic device (PLD), as generally designated by the reference numeral  500 . FPGA/PLD method  500  includes: providing a control signal from I 2 C 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 .  
         [0044]    An I 2 C bus  510  is used to control FPGA/PLD  520 . As is known to those skilled in the art, I 2 C bus  510  is a bi-directional two-wire serial bus that provides a communication link between integrated circuits. As known to those skilled in the art, 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 I 2 C bus  410  to allow the user to input the voltage at which the user wants to run the blades  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 .  
         [0045]    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 blades  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 blade voltage is compared. The reference voltage level represents the global system power of bladed architecture systems  100 , the maximum voltage accessible by any one blade  110 ,  120 ,  130 ,  140  hosted within bladed architecture system  100 . DC-to-DC converter  550  then generates the appropriate output voltage  560  for the blades  110 ,  120 ,  130 ,  140  to optimize performance of the blades  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 blades  110 ,  120 ,  130 ,  140  using the trim pins of DC-to-DC converter  550 .  
         [0046]    [0046]FIG. 6 illustrates a block diagram depicting a series of blades inside of the chassis of bladed architecture system  100  running at the same voltage, as generally designated by the reference numeral  600 . The shading of the individual blades indicates that each individual blade is operating at the same voltage level. Operating blades at the same voltage is typical in current bladed architecture system. In addition, the shading illustrates that each blade is operating at below a maximum performance level of that blade in order to remain under the maximum power allocated to the system as a whole. As discussed previously, bladed server systems are limited by an underlying power and thermal envelope. This is due to the heat produced within the blades 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 blades. As a result, the power limitation limits the voltage that the processors on the blade 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.  
         [0047]    [0047]FIG. 7 illustrates a block diagram depicting a series of blades inside of a bladed architecture chassis running at different voltages, as 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 blades 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 blade is now only using the requisite voltage level that is required for its particular function within the system. Because of the varying levels of voltage available to the individual blades, blades that require a higher voltage than the average can now operate at a more optimum level. Similarly, blades that require less power no longer require to be run at the same voltage level as the other blades. As a result, a more efficient system is created.  
         [0048]    It is to be appreciated that the principles disclosed herein may be applied to a system comprised of 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 blades. 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.  
         [0049]    While the systems and 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.  
         [0050]    For example, the disclosed system and method makes use of specific I 2 C devices that are used to received signals from an I 2 C bus. Other I 2 C devices could likewise be used. Thus, the devises 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 Applicants&#39; intention to limit the system or method described herein to any particular form of processor, blade, or specific blade architecture.  
         [0051]    Further examples exist throughout the disclosure, and it is not Applicants&#39; 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.