Task switching

• US 20060100986A1
• Filed: 10/28/2004
• Published: 05/11/2006
• Est. Priority Date: 10/28/2004
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: MacPherson, Mike
• Granted Patent: US 7,603,673 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 9/461 Saving or restoring of program or task context

Abstract

The present disclosure relates to resource management of a multi-threaded system by controlling when thread state is stored to memory and, more specifically, to attempting to increase the speed in which task switching occurs by controlling whether or not thread state stored to memory.

Claims

1. :

A method comprising;

detecting a context switch request;

halting a master thread;

estimating the retirement rate of a state associated with worker threads; and

determining, based at least in part upon the state retirement rate of the worker threads, if the worker threads should be halted and the worker threads'"'"' state saved to memory.

2. :

The method of claim 1, further comprising;

halting and saving the state of the worker threads to a memory if the rate of savings is greater than the state retirement rate.

3. :

The method of claim 2 wherein the rate of savings is assumed to be a portion of the bandwidth available to write to the memory.

4. :

The method of claim 2 further comprising, if the rate of savings is not greater than the retirement rate,

allowing the worker threads to naturally retire,

estimating the retirement rate of a state associated with worker threads; and

determining, based at least in part upon the state retirement rate of the worker threads, if the worker threads should be halted and the worker threads'"'"' state saved to memory.

5. :

The method of claim 1 wherein, estimating the retirement rate of a state associated with worker threads comprises;

monitoring the thread retirement rate of the worker threads; and

estimating the state retirement rate based at least in part upon the thread retirement rate.

6. :

The method of claim 5, wherein estimating the state retirement rate based at least in part upon the thread retirement rate includes accounting for worker threads having variable size thread states.

7. :

The method of claim 5 wherein, monitoring the thread retirement rate of the worker threads comprises utilizing structures primarily capable of thread scheduling.

8. :

The method of claim 1, further comprising;

based at least in part upon the estimation of state retirement rate, prioritizing the order in which worker threads will be halted and the worker threads'"'"' state saved.

9. :

The method of claim 8 further comprising;

if the rate of savings is greater than the state retirement rate, halting and saving the state of the worker threads to a memory.

10. :

The method of claim 9 further comprising, if the rate of savings is not greater than the state retirement rate;

allowing the worker threads to naturally retire,

estimating the retirement rate of a state associated with worker threads;

based at least in part upon the estimation of state retirement rate, prioritizing the order in which worker threads will be halted and the worker threads'"'"' state saved; and

determining, based at least in part upon the state retirement rate of the worker threads, if the worker threads should be halted and the worker threads'"'"' state saved to memory.

11. :

An article comprising;

a machine accessible medium having a plurality of machine accessible instructions, wherein when the instructions are executed, the instructions provide for;

detecting a context switch request;

halting a master thread;

estimating the retirement rate of a state associated with worker threads; and

determining, based at least in part upon the state retirement rate of the worker threads, if the worker threads should be halted and the worker threads'"'"' state saved to memory.

12. :

The article of claim 11, further comprising instructions providing for;

halting and saving the state of the worker threads to a memory if the rate of savings is greater than the state retirement rate.

13. :

The article of claim 12 wherein the rate of savings is assumed to be a portion of the bandwidth available to write to the memory.

14. :

The article of claim 12 further comprising instructions providing for, if the rate of savings is not greater than the retirement rate,

allowing the worker threads to naturally retire,

estimating the retirement rate of a state associated with worker threads; and

determining, based at least in part upon the state retirement rate of the worker threads, if the worker threads should be halted and the worker threads'"'"' state saved to memory.

15. :

The article of claim 11 wherein, the instructions providing for estimating the retirement rate of a state associated with worker threads comprise instructions providing for;

monitoring the thread retirement rate of the worker threads; and

estimating the state retirement rate based at least in part upon the thread retirement rate.

16. :

The article of claim 15, wherein the instructions providing for estimating the state retirement rate based at least in part upon the thread retirement rate includes instructions providing for accounting for worker threads having variable size thread states.

17. :

The article of claim 15 wherein, the instructions providing for monitoring the thread retirement rate of the worker threads comprises instructions providing for utilizing structures primarily capable of thread scheduling.

18. :

The article of claim 11, further comprising instructions providing for;

based at least in part upon the estimation of state retirement rate, prioritizing the order in which worker threads will be halted and the worker threads'"'"' state saved.

19. :

The article of claim 18 further comprising instructions providing for;

if the rate of savings is greater than the state retirement rate, halting and saving the state of the worker threads to a memory.

20. :

The article of claim 19 further comprising instructions providing for, if the rate of savings is not greater than the state retirement rate;

allowing the worker threads to naturally retire,

estimating the retirement rate of a state associated with worker threads;

based at least in part upon the estimation of state retirement rate, prioritizing the order in which worker threads will be halted and the worker threads'"'"' state saved; and

determining, based at least in part upon the state retirement rate of the worker threads, if the worker threads should be halted and the worker threads'"'"' state saved to memory.

21. :

An apparatus comprising;

a processor that is capable of executing a plurality of threads having state information,

a thread monitoring circuit that is capable of;

estimating the state retirement rate of the plurality of threads;

a thread dispatcher circuit that is capable of;

detecting a context switch;

determining, based at least in part upon the state retirement rate, if the plurality of threads should be halted and the threads'"'"' state information saved to a memory.

22. :

The apparatus of claim 21, wherein the thread dispatcher circuit that is further capable of;

halting and saving the state of the threads to a memory if the rate of savings is greater than the state retirement rate.

23. :

The apparatus of claim 22 wherein the rate of savings is assumed to be a portion of the bandwidth available to write to the memory.

24. :

The apparatus of claim 22 wherein the thread dispatcher circuit that is further capable of, if the rate of savings is not greater than the retirement rate;

allowing the threads to naturally retire,

determining, based at least in part upon the state retirement rate of the worker threads, if the worker threads should be halted and the worker threads'"'"' state saved to memory.

25. :

The apparatus of claim 21 wherein, the thread monitoring circuit is further capable of;

monitoring the thread retirement rate of the threads; and

estimating the state retirement rate based at least in part upon the thread retirement rate.

26. :

The apparatus of claim 25, wherein the thread monitoring circuit is further capable of;

estimating the state retirement rate based at least in part upon the thread retirement rate by accounting for worker threads having variable size thread states.

27. :

The apparatus of claim 25 wherein, the thread monitoring circuit is further capable of thread scheduling.

28. :

The apparatus of claim 21, wherein the thread dispatcher circuit is further capable of;

based at least in part upon the estimation of state retirement rate, prioritizing the order in which threads will be halted and the threads'"'"' state saved.

29. :

The apparatus of claim 21 wherein the processor includes a single chip multiprocessor.

30. :

The apparatus of claim 29 wherein the processor includes a register state of at least 128 kilobytes.

31. :

A system comprising;

a processor that is capable of executing a plurality of threads having state information,

a memory that is capable of storing the state information of the plurality of threads when the threads are not being executed by the processor;

a thread monitoring circuit that is capable of;

estimating the state retirement rate of the plurality of threads;

a thread dispatcher circuit that is capable of;

detecting a context switch;

determining, based at least in part upon the state retirement rate, if the plurality of threads should be halted and the threads'"'"' state information saved to the memory.

32. :

The system of claim 31, wherein the thread dispatcher circuit that is further capable of;

halting and saving the state of the threads to a memory if the rate of savings is greater than the state retirement rate.

33. :

The system of claim 32 wherein the rate of savings is assumed to be a portion of the bandwidth available to write to the memory.

34. :

The system of claim 32 wherein the thread dispatcher circuit that is further capable of, if the rate of savings is not greater than the retirement rate;

allowing the threads to naturally retire,

determining, based at least in part upon the state retirement rate of the worker threads, if the worker threads should be halted and the worker threads'"'"' state saved to memory.

35. :

The system of claim 31 wherein, the thread monitoring circuit is further capable of;

monitoring the thread retirement rate of the threads; and

estimating the state retirement rate based at least in part upon the thread retirement rate.

36. :

The system of claim 35, wherein the thread monitoring circuit is further capable of;

estimating the state retirement rate based at least in part upon the thread retirement rate by accounting for worker threads having variable size thread states.

37. :

The system of claim 35 wherein, the thread monitoring circuit is further capable of thread scheduling.

38. :

The system of claim 31, wherein the thread dispatcher circuit is further capable of;

based at least in part upon the estimation of state retirement rate, prioritizing the order in which threads will be halted and the threads'"'"' state saved.

39. :

The system of claim 31 wherein the processor includes a single chip multiprocessor.

40. :

The system of claim 39 wherein the processor includes a register state of at least 128 kilobytes.