Apparatus and method for power performance monitors for low-power program tuning

• US 20050138450A1
• Filed: 12/19/2003
• Published: 06/23/2005
• Est. Priority Date: 12/19/2003
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Hsieh, Cheng-Hsueh
• Granted Patent: US 7,287,173 B2
• Time in Patent Office: Days
• US Class Current: 713/320
• CPC Class Codes: G06F 8/4432 Reducing the energy consumption
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

In some embodiments, a method and apparatus for power performance monitors for low-power program tuning are described. In one embodiment, the method includes the computation of power consumption levels of instructions of an application. Once consumption levels are computed, instruction sequences of the application are identified that exhibit an excess power consumption level. For the identified instruction sequences, the application program is recompiled to reduce power consumption levels of one or more of the identified instruction sequences. Other embodiments are described and claimed.

Claims

1. A method comprising:

computing power consumption levels of instructions of an application program;

identifying instruction sequences of the application program having an excess power consumption level; and

recompiling the application program to reduce power consumption levels of one or more of the identified instruction sequences.

2. The method of claim 1, wherein computing power comprises:

executing micro-operations decoded from the instructions of the application program within one or more micro-architecture functional units;

updating, by each functional unit, a power consumption field of each micro-operation processed by the respective functional unit with a power consumption level of the respective functional unit required to process the respective micro-operation during micro-operation execution; and

prior to retiring each executed micro-operation, updating a power history buffer entry according to a value of each executed micro-operation'"'"'s power consumption field.

3. The method of claim 2, wherein updating a power consumption field comprises:

(i) determining a power consumption level of a functional unit for a program cycle;

(ii) identifying one or more micro-operations processed during the program cycle;

(iii) incrementing a value of a power consumption field of the one or more identified micro-operations by the determined power consumption level; and

(iv) repeating (i)-(iii) for each program cycle by each of one or more functional units.

4. The method of claim 3, wherein determining the power consumption level comprises:

querying a power consumption meter coupled to the functional unit; and

receiving a power consumption level measured by the power consumption meter during the program cycle.

5. The method of claim 3, wherein prior to incrementing, the method comprises:

dividing the determined power consumption level by a count of identified micro-operations during the program cycle to form a power consumption per cycle value;

incrementing the power consumption field of the identified micro-operations by the power consumption per cycle value;

updating an average power consumption meter of the function unit according to the power per consumption cycle value; and

updating a utilization meter of the functional unit for the program cycle.

6. The method of claim 3, wherein updating the power history buffer comprises:

(i) receiving an executed micro-operation;

(ii) identifying a program counter value associated with the executed micro-operation according to a program counter field of the executed micro-operation;

(iii) identifying a power consumption level associated with the executed micro-operation according to a power consumption field of the executed micro-operation;

(iv) incrementing an entry within the power history buffer corresponding to the identified program counter of the executed micro-operation by a value of the identified power consumption level of the executed micro-operation; and

(v) repeating (i)-(iv) for each received, executed micro-operation.

7. The method of claim 1, wherein identifying further comprises:

periodically querying a power history buffer to identify power consumed levels of the instructions of the application program;

detecting instructions having a power consumption level exceeding a predetermined power consumption level;

identifying, from the detected instructions, critical power path instruction sequences as instructions falling within a frequently executed instruction path having a high power consumption level; and

identifying, from the detected instructions, high power level instruction sequences as instruction sequences executed by functional units having an average power consumption level greater than a predetermined functional unit power consumption level.

8. The method of claim 1, wherein recompiling comprises:

replacing identified critical power path instruction sequences with alternate instruction sequences to reduced program power consumption levels by using the alternate instruction sequences.

9. The method of claim 1, wherein recompiling further comprises:

redistributing high power level instruction sequences to utilize functional units with a lower, average power consumption level.

10. The method of claim 1, further comprising:

sampling an idle time of one or more functional units used to execute identified high power level instruction sequences; and

issuing the high power instruction sequences to one or more functional units when utilization of the functional units is low to prohibit functional unit overheating.

11. An article of manufacture including a machine readable medium having stored thereon instructions which may be used to program a system to perform a method, comprising:

computing power consumption levels of instructions of an application program;

identifying instruction sequences of the application program having an excess power consumption level; and

recompiling the application program to reduce power consumption levels of one or more of the identified instruction sequences.

12. The article of manufacture of claim 11, wherein computing power comprises:

executing micro-operations decoded from the instructions of the application program within one or more micro-architecture functional units;

updating, by each functional unit, a power consumption field of each micro-operation processed by the respective functional unit with a power consumption level of the respective functional unit required to process the respective micro-operation during micro-operation execution; and

prior to retiring each executed micro-operation, updating a power history buffer entry according to a value of each executed micro-operation'"'"'s power consumption field.

13. The article of manufacture of claim 12, wherein updating a power consumption field comprises:

(i) determining a power consumption level of a functional unit for a program cycle;

(ii) identifying one or more micro-operations processed during the program cycle;

(iii) incrementing a value of a power consumption field of the one or more identified micro-operations by the determined power consumption level; and

(iv) repeating (i)-(iii) for each program cycle by each of one or more functional units.

14. The article of manufacture of claim 13, wherein determining the power consumption level comprises:

querying a power consumption meter coupled to the functional unit; and

receiving a power consumption level measured by the power consumption meter during the program cycle.

15. The article of manufacture of claim 13, wherein prior to incrementing, the method comprises:

dividing the determined power consumption level by a count of identified micro-operations during the program cycle to form a power consumption per cycle value;

incrementing the power consumption field of the identified micro-operations by the power consumption per cycle value;

updating an average power consumption meter of the function unit according to the power per consumption cycle value; and

updating a utilization meter of the functional unit for the program cycle.

16. The article of manufacture of claim 13, wherein updating the power history buffer comprises:

(i) receiving an executed micro-operation;

(ii) identifying a program counter value associated with the executed micro-operation according to a program counter field of the executed micro-operation;

(iii) identifying a power consumption level associated with the executed micro-operation according to a power consumption field of the executed micro-operation;

(iv) incrementing an entry within the power history buffer corresponding to the identified program counter of the executed micro-operation by a value of the identified power consumption level of the executed micro-operation; and

(v) repeating (i)-(iv) for each received, executed micro-operation.

17. The article of manufacture of claim 11, wherein identifying further comprises:

periodically querying a power history buffer to identify power consumed levels of the instructions of the application program;

detecting instructions having a power consumption level exceeding a predetermined power consumption level;

identifying, from the detected instructions, critical power path instruction sequences as instructions falling within a frequently executed instruction path having a high power consumption level; and

identifying, from the detected instructions, high power level instruction sequences as instruction sequences executed by functional units having an average power consumption level greater than a predetermined functional unit power consumption level.

18. The article of manufacture of claim 11, wherein recompiling comprises:

replacing identified critical power path instruction sequences with alternate instruction sequences to achieve reduced instruction power consumption levels by using the alternate instruction sequences.

19. The article of manufacture of claim 11, wherein recompiling further comprises:

redistributing high power level instruction sequences to utilize functional units with a lower, average power consumption level.

20. The article of manufacture of claim 11, further comprising:

sampling an idle time of one or more functional units used to execute identified high power level instruction sequences; and

issuing the high power instruction sequences to one or more functional units when utilization of the functional units is low to prohibit functional unit overheating.

21. An apparatus comprising:

at least one functional unit to execute micro-operations decoded from instructions of an application program, the functional unit to compute power consumption levels of instructions of an application program; and

a memory coupled to the functional unit, the memory including a compiler to recompile the application program to reduce power consumption levels of an instruction sequence identified as having an excess power consumption level.

22. The apparatus of claim 21, wherein the at least one functional unit further comprises:

a retirement unit to update a prosecution history buffer entry according to a value of a power consumption field of each executed micro-operation.

23. The apparatus of claim 21, wherein the at least one functional unit is to increment a power consumption field of each micro-operation by a power consumption level required to process the respective micro-operation.

24. The apparatus of claim 21, further comprising:

a power meter coupled to the at least one functional unit, the power meter to measure power consumed by the at least one functional unit during a program cycle.

25. The apparatus of claim 21, wherein the at least one functional unit further comprises:

an average power consumption meter, the at least one functional unit to update the average power consumption meter according to a power consumption per cycle value.

26. A system comprises:

a self-contained power source;

a processor coupled to the power source, the process comprising;

at least one functional unit to execute micro-operations decoded from instructions of an application program, the functional unit to compute power consumption levels of instructions of an application program; and

a memory coupled to the processor, the memory including a compiler to recompile the application program to reduce power consumption levels of an instruction sequence identified as having an excess power consumption level.

27. The system of claim 26, wherein the at least one functional further comprises:

a retirement unit to update a prosecution history buffer entry according to a value of a power consumption field of each executed micro-operation.

28. The system of claim 26, wherein the at least one functional unit is to increment a power consumption field of each micro-operation by a power consumption level required to process the respective micro-operation.

29. The system of claim 26, further comprising:

a memory controller coupled between the processor and the memory; and

an input/output controller coupled to the memory controller.

30. The system of claim 26, further comprising:

logic built on a same die as the at least one functional unit and coupled to the at least one functional unit to measure power consumed by the at least one functional unit during a program cycle; and

an integrated circuit package containing the die in which the logic, the at least one functional unit and the processor are built.