HARDWARE SUPPORTED HIGH PERFORMANCE LOCK SCHEMA

• US 20110161540A1
• Filed: 12/22/2010
• Published: 06/30/2011
• Est. Priority Date: 12/22/2009
• Status: Abandoned Application

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hou, Rui, Zhu, Zhen Bo, Chang, Xiao Tao, Yang, Yudong, Zeng, Hong Bo
• Application Number:
  US12/975,579
• Publication Number:
  US 20110161540A1
• Time in Patent Office: Days
• US Class Current: 710/200
• CPC Class Codes: G06F 2209/522 Manager
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms

Abstract

A method and apparatus for lock allocation control. When a processor core acquires a lock, other processor cores do not need to constantly poll memory to check whether the required lock is released. Instead, other processor cores will be in sleep state and the next processor core needed will be selectively woken up based on predetermined rule, such that an out-of-order lock contention procedure is turned into an in-order lock allocation procedure. By selectively waking up a processor core that is in sleep state, the method and apparatus can avoid occupying a large amount of bus bandwidth, can avoid cache misses, and can save power consumption of chip.

Claims

1. A method for performing lock allocation for a plurality of processor cores, and wherein a first processor core acquires a lock, while other processor cores that need to acquire said lock are in sleep state, the method including:

receiving a signal that the first processor core has released said lock;

determining a second processor core that should be woken up from other processor cores that need to acquire said lock and are in sleep state based on a predetermined rule for allocating said lock; and

waking up the second processor core to enable it to acquire said lock.

2. The method according to claim 1, further including:

creating a lock information storage table for said lock to record identifier of said lock, state value of said lock, identifier of at least one processor core that needs to acquire said lock and is in sleep state, and a predetermined rule for allocating said lock.

3. The method according to claim 2, further including:

updating information in the lock information storage table if the second processor core has acquired said lock.

4. The method according to claim 2, wherein the plurality of processor cores include remote processor cores and local processor cores, and said predetermined rule for allocating said lock includes:

allocating said lock to local processor cores preferentially if processor cores that need to acquire said lock and are in sleep state include both local processor cores and remote processor cores.

5. The method according to claim 4, wherein said predetermined rule for allocating said lock further includes:

preferentially allocating said lock to a remote processor core in a remote computer node that is physically closer to a first computer node where the first processor core is located if multiple remote computer nodes all contain remote processor cores that need to acquire said lock and are in sleep state.

6. The method according to claim 4, wherein the second processor core and the first processor core are located in different computer nodes respectively, and the method further including:

notifying a computer node where the second processor core is located to enable the computer node where the second processor core is located to wake up the second processor core that is in sleep state.

7. The method according to claim 6, further including:

confirming that the computer node where the second processor core is located returns control of said lock to the computer node where the first processor core is located after the second processor core has released said lock.

8. The method according to claim 6, further including:

confirming that the computer node where the second processor core is located delivers control of said lock to the computer node where a next processor core that needs to be woken up is located after the second processor core has released said lock.

9. The method according to claim 4, wherein the identifier of at least one processor core that needs to acquire said lock and is in sleep state recorded in the lock information storage table is an identifier of a local processor core that needs to acquire said lock and is in sleep state, and the lock information storage table further records identifiers of remote computer nodes where remote processor cores that need to acquire said lock and are in sleep state are located.

10. A lock allocation controller for performing lock allocation for a plurality of processor cores, and wherein a first processor core acquires a lock, while other processor cores that need to acquire said lock are in sleep state, the lock allocation controller including:

a lock state change receiving means for receiving a signal that the first processor core has released said lock;

a target core determining means for determining a second processor core that is in sleep state and should be woken up from other processor cores that need to acquire said lock and are in sleep state based on predetermined rule for allocating said lock; and

a target core waking up means for waking up the second processor core to enable it to acquire said lock.

11. The lock allocation controller according to claim 10, further including:

a lock information storage table that is created for said lock for recording an identifier of said lock, state value of said lock, an identifier of at least one processor core that needs to acquire said lock and is in sleep state, and a predetermined rule for allocating said lock.

12. The lock allocation controller according to claim 11, wherein the lock information storage table is updated if the second processor core has acquired said lock.

13. The lock allocation controller according to claim 11, wherein the plurality of processor cores include remote processor cores and local processor cores, and said predetermined rule for allocating said lock includes:

preferentially allocating said lock to local processor cores if processor cores that need to acquire said lock and are in sleep state include both local processor cores and remote processor cores.

14. The lock allocation controller according to claim 13, wherein said predetermined rule for allocating said lock further includes:

preferentially allocating said lock to a remote processor core in a remote computer node that is physically closer to a first computer node where the first processor core is located if multiple remote computer nodes all contain remote processor cores that need to acquire said lock and are in sleep state.

15. The lock allocation controller according to claim 13, wherein the second processor core and the first processor core are located in different computer nodes respectively, and the lock allocation controller further including:

an inter-node communicating means for notifying a computer node where the second processor core is located to enable the computer node where the second processor core is located to wake up the second processor core that is in sleep state.

16. The lock allocation controller according to claim 15, the inter-node communicating means is further adapted to confirm that the computer node where the second processor core is located returns control of said lock to the first computer node where the first processor core is located after the second processor core has released said lock.

17. The lock allocation controller according to claim 15, the inter-node communicating means is further used to confirm that a second computer node where the second processor core is located delivers control of said lock to the computer node where a next processor core that needs to be woken up is located after the second processor core has released said lock.

18. The lock allocation controller according to claim 13, wherein an identifier of at least one processor core that needs to acquire said lock and is in sleep state recorded in the lock information storage table is an identifier of a local processor core that needs to acquire said lock and is in sleep state, and the lock information storage table further records identifiers of remote computer nodes where remote processor cores that need to acquire said lock and are in sleep state are located.

19. A computer system comprising:

a plurality of processor cores;

at least one cache; and

lock allocation controller for performing lock allocation for a plurality of processor cores, and wherein a first processor core acquires a lock, while other processor cores that need to acquire said lock are in sleep state, the lock allocation controller including;

a lock state change receiving means for receiving a signal that the first processor core has released said lock;

a target core determining means for determining a second processor core that is in sleep state and should be woken up from other processor cores that need to acquire said lock and are in sleep state based on predetermined rule for allocating said lock; and

a target core waking up means for waking up the second processor core to enable it to acquire said lock.