Transactional lock elision with delayed lock checking

• US 10,275,290 B2
• Filed: 08/14/2016
• Issued: 04/30/2019
• Est. Priority Date: 03/26/2013
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Michael, Maged M., Mitran, Marcel, Ohmacht, Martin, Wang, Kai-Ting Amy
• Primary Examiner(s): Tran, Loc
• Application Number:
  US15/236,475
• Publication Number:
  US 20160371128A1
• Time in Patent Office: 989 Days
• CPC Class Codes: G06F 12/1475 in a virtual system, e.g. with translation means
• CPC Class Codes: G06F 16/2343 Locking methods, e.g. distributed locking or locking implementation details
• CPC Class Codes: G06F 2212/1052 Security improvement
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0637 Permissions
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 9/466 Transaction processing
• CPC Class Codes: G06F 9/467 Transactional memory G06F9/528 takes precedence
• CPC Class Codes: G06F 9/524 Deadlock detection or avoidance

Abstract

A computer-implemented method includes the following operations. A transactional lock elision transaction including a critical section is executed. The critical section is processed. After the processing of the critical section and prior to a commit point in the transactional lock elision transaction, a status of a lock is checked. Responsive to a determination that a status of the lock is free, a result of the transactional lock elision transaction is committed.

Claims

1. A computer-implemented method, comprising:

executing a transactional lock elision transaction including a critical section;

processing the critical section;

checking, after the processing of the critical section and prior to a commit point in the transactional lock elision transaction, a status of a lock;

committing, responsive to a determination that a status of the lock is free, a result of the transactional lock elision transaction;

calculating a cost associated with the lock being checked;

analyzing the cost; and

identifying, using a result of the analyzing, one of;

a lock read early or

a lock read late.

2. The method of claim 1, further comprising:

storing results of the identifying into a database; and

using the stored results stored to guide subsequent runs of a similar transaction.

3. The method of claim 1, wherein

a time window from reading the lock early to a commit time is greater than a time window from reading the lock late to the commit time,

a probability of conflict on the lock in deferred locking is less than a probability of conflict on the lock in conventional locking.

4. A computer hardware system, comprising

a hardware processor configured to initiate the following operations:

executing a transactional lock elision transaction including a critical section;

processing the critical section;

checking, after the processing of the critical section and prior to a commit point in the transactional lock elision transaction, a status of a lock;

committing, responsive to a determination that a status of the lock is free, a result of the transactional lock elision transactions;

calculating a cost associated with the lock being checked;

analyzing the cost; and

identifying, using a result of the analyzing, one of;

a lock read early or

a lock read late.

5. The system of claim 4, wherein the hardware processor is further configured to initiate the operations of:

storing results of the identifying into a database; and

using the stored results stored to guide subsequent runs of a similar transaction.

6. The system of claim 4, wherein

a time window from reading the lock early to a commit time is greater than a time window from reading the lock late to the commit time,

a probability of conflict on the lock in deferred locking is less than a probability of conflict on the lock in conventional locking.

7. The system of claim 4, wherein the hardware processor is further configured to initiate the operation of:

selecting, responsive to a determination that the status of the lock is not free, an action from a set of alternative actions.

8. The system of claim 7, wherein

the set of alternate actions includes

performing a short spin loop and

performing a wait-notify.

9. The system of claim 7, wherein the hardware processor is further configured to initiate the operation of:

performing at least one alternate action selected from the set of alternate actions.

10. A computer program product, comprising:

a storage hardware device having stored therein program code,

the program code, when executed by a computer hardware system, causes the computer hardware system to perform;

executing a transactional lock elision transaction including a critical section;

processing the critical section;

checking, after the processing of the critical section and prior to a commit point in the transactional lock elision transaction, a status of a lock;

committing, responsive to a determination that a status of the lock is free, a result of the transactional lock elision transaction;

calculating a cost associated with the lock being checked;

analyzing the cost; and

identifying, using a result of the analyzing, one of;

a lock read early or

a lock read late.

11. The computer program product of claim 10, wherein the program code further causes the computer hardware system to perform:

storing results of the identifying into a database; and

using the stored results stored to guide subsequent runs of a similar transaction.

12. The computer program product of claim 10, wherein

a time window from reading the lock early to a commit time is greater than a time window from reading the lock late to the commit time,

a probability of conflict on the lock in deferred locking is less than a probability of conflict on the lock in conventional locking.

13. The computer program product of claim 10, wherein the program code further causes the computer hardware system to perform:

selecting, responsive to a determination that the status of the lock is not free, an action from a set of alternative actions.

14. The computer program product of claim 13, wherein

the set of alternate actions includes

performing a short spin loop and

performing a wait-notify.

15. The computer program product of claim 13, wherein the program code further causes the computer hardware system to perform:

performing at least one alternate action selected from the set of alternate actions.