System and method for selective timer rate limiting

• US 9,904,575 B2
• Filed: 05/15/2013
• Issued: 02/27/2018
• Est. Priority Date: 05/15/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Kumar, Derek R.
• Primary Examiner(s): Tsai, Henry
• Assistant Examiner(s): Hassan, Aurangzeb
• Application Number:
  US13/895,264
• Publication Number:
  US 20140344820A1
• Time in Patent Office: 1,749 Days
• Field of Search: None
• CPC Class Codes: G06F 13/24 using interrupt G06F13/32 takes precedence
• CPC Class Codes: G06F 13/26 with priority control
• CPC Class Codes: G06F 9/4812 by interrupt, e.g. masked
• CPC Class Codes: G06F 9/4843 by program, e.g. task dispatcher, supervisor, operating system
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A method and apparatus of a device that rate-limits the execution of a timer is described. The device receives a timer that includes an initial execution timer and a timer priority. If the timer priority is low, the device rate-limits the execution of the timer based on a suppression period associated with the timer priority. In order to rate-limit the execution of the timer, the device determines the suppression period based on the timer priority and schedules the timer to execute at the end of the suppression period. The device further schedules the timer to execute at the initial exertion time when the timer priority is high.

Claims

1. A non-transitory machine-readable medium having executable instructions to cause one or more processing units to perform a method to rate-limit an execution of a timer, the method comprising:

receiving a timer, wherein the timer includes a periodicity, an execution time based on the periodicity, a timer priority and the timer is a time-driven interrupt source to trigger a periodic activity of an application; and

if the timer priority is below a threshold, rate-limiting the execution of the timer based on a suppression period derived from the timer priority, wherein there are different suppression periods for different timer priorities and the suppression period is greater than the periodicity of the timer, wherein the rate-limiting the execution of the timer comprises,

determining the suppression period based on the timer priority, and

scheduling the timer to execute after the suppression period; and

if the timer priority at or above the threshold, scheduling the timer to execute at the initial execution time.

2. The non-transitory machine-readable medium of claim 1, wherein the timer priority is below the threshold when the timer is associated with a low priority task.

3. The non-transitory machine-readable medium of claim 1, wherein the timer priority is at or above the threshold when the timer is associated with a high priority task.

4. The non-transitory machine-readable medium of claim 1, wherein the timer is a software timer.

5. The non-transitory machine-readable medium of claim 1, wherein the suppression period is greater than a multiple of the periodicity of the timer.

6. The non-transitory machine-readable medium of claim 1, wherein the suppression period is equal to a multiple of the periodicity of the timer.

7. A device to rate-limit an execution of a timer, the device comprising:

a processor;

a memory coupled to the processor though a bus; and

a process executed from the memory by the processor causes the processor to receive a timer, wherein the timer includes a periodicity, an execution time based on the periodicity, a timer priority and the timer is a time-driven interrupt source to trigger a periodic activity of an application, and if the timer priority is below a threshold, rate-limit the execution of the timer based on a suppression period derived from the timer priority, wherein there are different suppression periods for different timer priorities and the suppression period is greater than the periodicity of the timer, wherein the rate-limiting the execution of the timer comprises, determining the suppression period based on the timer priority, and scheduling the timer to execute after the suppression period, and if the timer priority at or above the threshold, schedule the timer to execute at the initial execution time.

8. The device of claim 7, wherein the timer is a software timer.

9. The device of claim 7, wherein the timer priority is below the threshold when the timer is associated with a low priority task.

10. The device of claim 7, wherein the timer priority is at or above the threshold when the timer is associated with a high priority task.

11. The device of claim 7, wherein the suppression period is greater than a multiple of the periodicity of the timer.

12. The device of claim 7, wherein the suppression period is equal to a multiple of the periodicity of the timer.

13. A computer implemented method for rate-limiting an execution of a timer, the method comprising:

receiving a timer, wherein the timer includes a priority, an execution time based on the periodicity, a timer priority and the timer is a time-driven interrupt source to trigger a periodic activity of an application; and

if the timer priority is below a threshold, rate-limiting the execution of the timer based on a suppression period derived from the timer priority, wherein there are different suppression periods for different timer priorities and the suppression period is greater than the periodicity of the timer, wherein the rate-limiting the execution of the timer comprises,

determining the suppression period based on the timer priority, and

scheduling the timer to execute after the suppression period; and

if the timer priority at or above the threshold, scheduling the timer to execute at the initial execution time.

14. The method of claim 13, wherein the timer priority is below the threshold when the timer is associated with a low priority task.

15. The method of claim 13, wherein the timer priority is at or above the threshold when the timer is associated with a high priority task.

16. The method of claim 13, wherein the suppression period is greater than a multiple of the periodicity of the timer.

17. The method of claim 13, wherein the suppression period is equal to a multiple of the periodicity of the timer.