Shielding real-time workloads from OS jitter due to expedited grace periods

• US 10,140,131 B2
• Filed: 08/11/2016
• Issued: 11/27/2018
• Est. Priority Date: 08/11/2016
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: McKenney, Paul E.
• Primary Examiner(s): Abbaszadeh, Jaweed A
• Assistant Examiner(s): Derose, Volvick
• Application Number:
  US15/234,265
• Publication Number:
  US 20180046468A1
• Time in Patent Office: 838 Days
• Field of Search: 713 2
• CPC Class Codes: G06F 15/177 Initialisation or configuration control processor initialisation G06F9/4405
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0685 Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays
• CPC Class Codes: G06F 9/4401 Bootstrapping security arrangements therefor G06F21/57
• CPC Class Codes: G06F 9/4406 Loading of operating system
• CPC Class Codes: G06F 9/4881 Scheduling strategies for dispatcher, e.g. round robin, multi-level priority queues
• CPC Class Codes: G06F 9/5016 the resource being the memory
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms

Abstract

A technique for shielding real-time workloads from operating system (OS) jitter due to expedited read-copy update (RCU) grace periods. In accordance with the disclosed technique, a kernel parameter is set to indicate that expedited RCU grace periods are to be suppressed. The kernel parameter is checked to see if it is set. A normal non-expedited RCU grace period is invoked in response to attempted invocation of an expedited RCU grace period if the check reveals that the kernel parameter is set.

Claims

1. A system, comprising:

a plurality of CPUs;

a memory coupled to said CPUs, said memory including a computer readable storage medium tangibly embodying at least one program of instructions executable by said CPUs to perform operations for shielding real-time workloads from operating system (OS) jitter due to expedited read-copy update (RCU) grace periods, said operations comprising;

setting a kernel parameter indicating that expedited RCU grace periods are to be suppressed;

checking said kernel parameter to determine if it is set; and

invoking a normal non-expedited RCU grace period in response to attempted invocation of an expedited RCU grace period if said checking reveals that said kernel parameter is set.

2. The system of claim 1, wherein said checking said kernel parameter is performed in response to said attempted invocation of said expedited RCU grace period.

3. The system of claim 1, wherein said checking said kernel parameter is implemented within an expedited RCU grace period function.

4. The system of claim 1, wherein said invoking of said normal RCU grace period is implemented within an expedited RCU grace period function.

5. The system of claim 1, wherein said kernel parameter is set either at kernel boot time or at kernel runtime.

6. The system of claim 1, wherein said kernel parameter is set following the end of a non-in-kernel bootup phase.

7. The system of claim 1, wherein said kernel parameter is set prior to the end of an in-kernel boot sequence prior to an init process being spawned, said kernel parameter being set if a second kernel parameter was set to specify that expedited RCU grace periods are to be suppressed only during kernel runtime.

8. A computer program product, comprising:

one or more non-transitory computer readable data storage media;

program instructions stored on said one or more computer readable data storage media for programming a data processing platform having a plurality of CPUs to perform operations for shielding real-time workloads from operating system (OS) jitter due to expedited read-copy update (RCU) grace periods, said operations comprising;

setting a kernel parameter indicating that expedited RCU grace periods are to be suppressed;

checking said kernel parameter to determine if it is set; and

invoking a normal non-expedited RCU grace period in response to attempted invocation of an expedited RCU grace period if said checking reveals that said kernel parameter is set.

9. The computer program product of claim 8, wherein said checking said kernel parameter is performed in response to said attempted invocation of said expedited RCU grace period.

10. The computer program product of claim 8, wherein said checking said kernel parameter is implemented within an expedited RCU grace period function.

11. The computer program product of claim 8, wherein said invoking of said normal RCU grace period is implemented within an expedited RCU grace period function.

12. The computer program product of claim 8, wherein said kernel parameter is set following the end of a non-in-kernel bootup phase.

13. The computer program product of claim 8, wherein said kernel parameter is set prior to the end of an in-kernel boot sequence prior to an init process being spawned, said kernel parameter being set if a second kernel parameter was set to specify that expedited RCU grace periods are to be suppressed only during kernel runtime.