System and method for controlling central processing unit power based on inferred workload parallelism

Patent metadata

Field	Value
Publication number	US-9563250-B2
Application number	US-94414010-A
Country	US
Kind code	B2
Filing date	Nov 11, 2010
Priority date	Dec 16, 2009
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

A method of dynamically controlling power within a multicore CPU is disclosed and may include receiving a degree of parallelism in a workload of a zeroth core and determining whether the degree of parallelism in the workload of the zeroth core is equal to a first wake condition. Further, the method may include determining a time duration for which the first wake condition is met when the degree of parallelism in the workload of the zeroth core is equal to the first wake condition and determining whether the time duration is equal to a first confirm wake condition. The method may also include invoking an operating system to power up a first core when the time duration is equal to the first confirm wake condition.

First claim

What is claimed is:

1. A method of dynamically controlling power within a multicore central processing unit (CPU), the method comprising:
determining a number of operating system scheduler ready-to-run queues that are available for scheduling on the multicore CPU;
calculating a degree of parallelism in a workload of a zeroth core of the multicore CPU, wherein the degree of parallelism comprises a number of ready-to-run threads in the available operating system scheduler ready-to-run queues;
determining that the number of ready-to-run threads exceeds a first threshold value for a first time duration that exceeds a second threshold value, wherein the first threshold value is set for triggering a core wake and the second threshold value is set for confirming the core wake;
calculating a system load value for the multicore CPU based on a run queue value of the zeroth core and an operating frequency of the zeroth core; and
when the number of ready-to-run threads exceeds the first threshold value for the first time duration that exceeds the second threshold value and the system load value meets a predetermined condition, powering up a first core of the multicore CPU to execute at least one of the available operating system scheduler ready-to-run queues, wherein the system load value indicates a number of powered cores for operation of the multicore CPU.

2. The method of claim 1 , wherein the degree of parallelism comprises a total number of tasks, threads, or a combination thereof waiting on one or more ready-to-run queues of an operating system scheduler, a number of tasks, threads, or a combination thereof actually running on the zeroth core, or a combination thereof.

3. The method of claim 1 , further comprising:
invoking an operating system to power up the first core when the second threshold value has been exceeded.

4. The method of claim 3 , further comprising:
invoking the operating system to add the first core to a set of schedulable resources.

5. The method of claim 4 , further comprising:
receiving a degree of parallelism in a workload on the zeroth core and the first core; and
determining whether the degree of parallelism in the workload on the zeroth core and the first core is equal to a first sleep condition.

6. The method of claim 5 , further comprising:
determining a second time duration for which the first sleep condition is met when the degree of parallelism in the workload on the zeroth core and the first core is equal to the first sleep condition; and
determining whether the second time duration for which the first sleep condition is met is equal to a first confirm sleep condition.

7. The method of claim 6 , further comprising:
invoking the operating system to save a current state of the first core, when the second time duration for which the first sleep condition is met is equal to the first sleep condition.

8. The method of claim 7 , further comprising:
invoking the operating system to power down the first core.

9. The method of claim 8 , further comprising:
invoking the operating system to remove the first core from the set of schedulable resources.

10. A wireless device, comprising:
means for determining a number of operating system scheduler ready-to-run queues that are available for scheduling on a multicore central processing unit (CPU);
means for calculating a degree of parallelism in a workload of a zeroth core of the multicore CPU, wherein the degree of parallelism comprises a number of ready-to-run threads in the available operating system scheduler ready-to-run queues;
means for determining that the number of ready-to-run threads exceeds a first threshold value for a first time duration that exceeds a second threshold value, wherein the first threshold value is set for triggering a core wake and the second threshold value is set for confirming the core wake;
means for calculating a system load value for the multicore CPU based on a run queue value of the zeroth core and an operating frequency of the zeroth core; and
means for, when the number of ready-to-run threads exceeds the first threshold value for the first time duration that exceeds the second threshold value and the system load value meets a predetermined condition, powering up a first core of the multicore CPU to execute at least one of the available operating system scheduler ready-to-run queues, wherein the system load value indicates a number of powered cores for operation of the multicore CPU.

11. The wireless device of claim 10 , wherein the degree of parallelism comprises a total number of tasks, threads, or a combination thereof waiting on one or more ready-to-run queues of an operating system scheduler, a number of tasks, threads, or a combination thereof actually running on the zeroth core, or a combination thereof.

12. The wireless device of claim 10 , further comprising:
means for invoking an operating system to power up the first core when the second threshold value has been exceeded.

13. The wireless device of claim 12 , further comprising:
means for invoking the operating system to add the first core to a set of schedulable resources.

14. The wireless device of claim 13 , further comprising:
means for receiving a degree of parallelism in a workload on the zeroth core and the first core; and
means for determining whether the degree of parallelism in the workload on the zeroth core and the first core is equal to a first sleep condition.

15. The wireless device of claim 14 , further comprising:
means for determining a second time duration for which the first sleep condition is met when the degree of parallelism in the workload on the zeroth core and the first core is equal to the first sleep condition; and
means for determining whether the second time duration for which the first sleep condition is met is equal to a first confirm sleep condition.

16. The wireless device of claim 15 , further comprising:
means for invoking the operating system to save a current state of the first core, when the second time duration for which the first sleep condition is met is equal to the first sleep condition.

17. The wireless device of claim 16 , further comprising:
means for invoking the operating system to power down the first core.

18. The wireless device of claim 17 , further comprising:
means for invoking the operating system to remove the first core from the set of schedulable resources.

19. A wireless device, comprising:
a processor configured with processor-executable instructions to perform operations comprising:
determining a number of operating system scheduler ready-to-run queues, the ready-to-run queues comprising at least one of a task or a thread available for scheduling on a multicore central processing unit (CPU);
calculating a degree of parallelism in a workload of a zeroth core of the multicore CPU, wherein the degree of parallelism comprises a number of ready-to-run threads in the available operating system scheduler ready-to-run queues;
determining that the number of ready-to-run threads exceeds a first threshold value for a first time duration that exceeds a second threshold value, wherein the first threshold value is set for triggering a core wake and the second threshold value is set for confirming the core wake;
calculating a system load value for the multicore CPU based on a run queue value of the zeroth core and an operating frequency of the zeroth core; and
when the number of ready-to-run threads exceeds the first threshold value for the first time duration that exceeds the seco

Assignees

• Rychlik Bohuslav
• Glenn Robert A
• Iranli Ali
• Salsbery Brian J
• Sur Sumit
• Thomson Steven S
• Qualcomm Inc

Inventors

• Rychlik Bohuslav
• Glenn Robert A
• Iranli Ali
• Salsbery Brian J
• Sur Sumit
• Thomson Steven S

Classifications

• G06F1/3203 Primary

  Power management, i.e. event-based initiation of a power-saving mode · CPC title

• G06F1/324

  by lowering clock frequency · CPC title

• G06F1/3296

  by lowering the supply or operating voltage · CPC title

• G06F1/3287

  by switching off individual functional units in the computer system · CPC title

• Y02B60/1217

  Cross-Sectional Technologies · mapped topic