Adjustment of a sleep duration for a process based on an expected time for securing a spinlock

• US 10,228,985 B2
• Filed: 11/03/2017
• Issued: 03/12/2019
• Est. Priority Date: 10/24/2016
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Burke, Seamus J., Nguyen, Trung N., Rasor, Louis A.
• Primary Examiner(s): Patel, Nimesh G
• Application Number:
  US15/803,705
• Publication Number:
  US 20180121256A1
• Time in Patent Office: 494 Days
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

A computational device maintains a spinlock for exclusive access of a resource by a process of a plurality of processes. In response to determining by the process that a turn for securing the spinlock has not arrived for the process, a sleep duration is determined for the process, prior to making a next attempt to secure the spinlock.

Claims

1. A method, comprising:

maintaining, by a computational device, a spinlock for exclusive access of a resource by a process of a plurality of processes; and

in response to determining by the process that a turn indicated by a ticket number of the process for securing the spinlock has not arrived for the process, determining a sleep duration for the process based on a number of tickets remaining to be processed for securing the spinlock and an average time duration to process a ticket; and

entering, by the process, a sleep mode the sleep duration.

2. The method of claim 1, wherein the sleep duration is determined prior to making a next attempt to secure the spinlock.

3. The method of claim 1, wherein the a sleep duration for the process is determined based on computing a product of a number of tickets remaining to be processed for securing the spinlock for the process, and an average time duration to process a ticket.

4. The method of claim 1, wherein the determining of the sleep duration for the process further comprises:

spinning the process for a predetermined number of processor cycles and determining how many tickets have been processed during the predetermined number of processor cycles; and

determining the average time duration to process a ticket based on determining how many tickets have been processed during the predetermined number of processor cycles.

5. The method of claim 1, wherein the plurality of processes are assigned sequential ticket numbers.

6. The method of claim 5, wherein the plurality of processes secure the spinlock in sequence, based on the sequentially assigned ticket numbers, and wherein the process is permitted to enter a critical section is which a shared resource is accessed, in response to arriving of the turn indicated by the ticket number of the process.

7. A system, comprising:

a memory;

a processor coupled to the memory, wherein the processor performs operations, the operations comprising;

maintaining a spinlock for exclusive access of a resource by a process of a plurality of processes; and

in response to determining by the process that a turn indicated by a ticket number of the process for securing the spinlock has not arrived for the process, determining a sleep duration for the process based on a number of tickets remaining to be processed for securing the spinlock and an average time duration to process a ticket; and

entering, by the process, a sleep mode the sleep duration.

8. The system of claim 7, wherein the sleep duration is determined prior to making a next attempt to secure the spinlock.

9. The system of claim 7, wherein the a sleep duration for the process is determined based on computing a product of a number of tickets remaining to be processed for securing the spinlock for the process, and an average time duration to process a ticket.

10. The system of claim 7, wherein the determining of the sleep duration for the process further comprises:

spinning the process for a predetermined number of processor cycles and determining how many tickets have been processed during the predetermined number of processor cycles; and

determining the average time duration to process a ticket based on determining how many tickets have been processed during the predetermined number of processor cycles.

11. The system of claim 7, wherein the plurality of processes are assigned sequential ticket numbers.

12. The system of claim 11, wherein the plurality of processes secure the spinlock in sequence, based on the sequentially assigned ticket numbers, and wherein the process is permitted to enter a critical section is which a shared resource is accessed, in response to arriving of the turn indicated by the ticket number of the process.

13. A computer program product, the computer program product comprising a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code configured to perform operations, the operations comprising:

maintaining a spinlock for exclusive access of a resource by a process of a plurality of processes; and

in response to determining by the process that a turn indicated by a ticket number of the process for securing the spinlock has not arrived for the process, determining a sleep duration for the process based on a number of tickets remaining to be processed for securing the spinlock and an average time duration to process a ticket; and

entering, by the process, a sleep mode the sleep duration.

14. The computer program product of claim 13, wherein the sleep duration is determined prior to making a next attempt to secure the spinlock.

15. The computer program product of claim 13, wherein the a sleep duration for the process is determined based on computing a product of a number of tickets remaining to be processed for securing the spinlock for the process, and an average time duration to process a ticket.

16. The computer program product of claim 13, wherein the determining of the sleep duration for the process further comprises:

spinning the process for a predetermined number of processor cycles and determining how many tickets have been processed during the predetermined number of processor cycles; and

determining the average time duration to process a ticket based on determining how many tickets have been processed during the predetermined number of processor cycles.

17. The computer program product of claim 13, wherein the plurality of processes are assigned sequential ticket numbers.

18. The computer program product of claim 17, wherein the plurality of processes secure the spinlock in sequence, based on the sequentially assigned ticket numbers, and wherein the process is permitted to enter a critical section is which a shared resource is accessed, in response to arriving of the turn indicated by the ticket number of the process.