Common scheduling and synchronization primitives

• US 8,387,075 B1
• Filed: 03/28/2008
• Issued: 02/26/2013
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: McCann, Peter J., Gould, Christopher M., Brown, Jeffrey A.
• Primary Examiner(s): Sough, S.
• Assistant Examiner(s): Yun, Carina
• Application Number:
  US12/079,648
• Time in Patent Office: 1,796 Days
• Field of Search: None
• US Class Current: 719/328
• CPC Class Codes: G06F 9/445 Program loading or initiating bootstrapping G06F9/4401; security arrangements for program loading or initiating G06F21/57
• CPC Class Codes: G06F 9/4812 by interrupt, e.g. masked
• CPC Class Codes: G06F 9/4825 Interrupt from clock, e.g. time of day
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores
• CPC Class Codes: G06F 9/545 where tasks reside in different layers, e.g. user- and kernel-space

Abstract

Described are techniques for executing code performing one or more operations corresponding to scheduling and synchronization primitives. During execution of the code, a call is performed using an application programming interface requesting a first of the operations corresponding to one of said scheduling and synchronization primitives. During runtime in response to said call, it is determined whether to perform the first operation. The determining step uses a set of one or more criteria indicating conditions as to when the scheduling and synchronization primitives are allowed to be performed. The one or more criteria are determined in accordance with a plurality of different platforms. If it is determined that the first operation is allowable and the first operation is to be performed, then the code can be executed on each of the different platforms in a privileged execution mode and a non-privileged execution mode.

Claims

1. A method of executing code performing one or more operations corresponding to scheduling and synchronization primitives, the method comprising:

performing, by said code during execution of said code, a call using an application programming interface requesting a first of said operations corresponding to one of said scheduling and synchronization primitives; and

determining, during runtime in response to said call, whether to perform said first operation, said determining using a set of one or more criteria indicating conditions as to when said scheduling and synchronization primitives are allowed to be performed, said one or more criteria being determined in accordance with a plurality of different platforms, if said determining determines that said first operation is allowable and said first operation is to be performed, then said code is allowed to be executed on each of said different platforms in a privileged execution mode and a non-privileged execution mode, wherein first code of the application programming interface provides a same set of functionality for both the privileged execution mode and the non-privileged execution mode, said same set of functionality including functionality in connection with a deferred procedure call and an interrupt service routine, wherein the first code of the application programming interface simulates functionality in connection with any of a deferred procedure call executed in the non-privileged execution mode and an interrupt service routine executed in the non-privileged execution mode using threads executed in the non-privileged execution mode.

2. The method of claim 1, wherein said conditions indicate allowable execution contexts using an execution level and a spin lock held indicator, said execution level indicating a runtime execution context level associated with said code at a current execution point, said spin lock held indicator providing a runtime indication as to whether a spin lock is currently acquired at said current execution point.

3. The method of claim 2, wherein said execution level is set to one of a plurality of execution level values, said plurality of execution level values including a thread level, a deferred procedure call level and an interrupt level, said thread level indicating that said current execution point corresponds to a body of code associated with a thread or a deferred work item, said deferred procedure call level indicating that said current execution point corresponds to a body of code associated with a deferred procedure call or a timer, and said interrupt level indicating that said current execution point corresponds to a body of code associated with an interrupt service routine.

4. The method of claim 3, wherein said code includes a first call using said application programming interface to perform one of said operations in connection with a mutual exclusion lock, a spin lock, a condition variable, a semaphore, and an event, and said application programming interface provides an interface to instantiate an object corresponding to a thread, a deferred procedure call, or an interrupt service routine.

5. The method of claim 2, further comprising:

updating said execution level and said spin lock held indicator during execution of said code to reflect a current runtime execution state of said code.

6. The method of claim 2, wherein said execution level and said spin lock held indicator are examined prior to performing said first operation to determine whether to perform said first operation.

7. The method of claim 1, wherein each of said plurality of different platforms includes at least one of an operating system or hardware which is different from another of said plurality of different platforms.

8. The method of claim 1, wherein said application programming interface provides an interface to a code module that performs said one or more operations when said code executes in a non-privileged that is user mode, and performs said one or more operations when said code executes in a privileged mode that is kernel mode.

9. The method of claim 1, wherein, if said code executes in a user mode that is said non-privileged execution mode, said first operation is performed in accordance with a set of semantics, and if said code executes in a kernel mode that is said privileged execution mode, said first operation is performed in accordance with said set of semantics so that runtime behavior exhibited when said first operation is performed while executing in said user mode is similar to runtime behavior exhibited when said first operation is performed while executing in said kernel mode.

10. The method of claim 1, wherein said scheduling and synchronization primitives perform operations on objects and said application programming interface includes one or more methods which perform said operations on said objects.

11. A non-transitory computer readable medium comprising code stored thereon for providing a set of one or more scheduling and synchronization primitives, the non-transitory computer readable medium comprising code stored thereon for:

providing an application programming interface for performing one or more operations, each of said one or more operations corresponding to one of said scheduling and synchronization primitives;

providing a set of one or more criteria indicating conditions as to when said scheduling and synchronization primitives are allowed to be performed; and

determining, using said one or more criteria during execution of other code, whether to perform a requested one of said operations, said other code making a call using said application programming interface to perform said requested operation, said one or more criteria being determined in accordance with a plurality of different platforms, if said determining determines that said requested one of said operations is allowable and said requested operation is to be performed, then said other code is allowed to be executed on each of said different platforms in a privileged execution mode and a non-privileged execution mode, wherein first code of the application programming interface provides a same set of functionality for both the privileged execution mode and the non-privileged execution mode, said same set of functionality including functionality in connection with a deferred procedure call and an interrupt service routine, wherein the first code of the application programming interface simulates functionality in connection with any of a deferred procedure call executed in the non-privileged execution mode and an interrupt service routine executed in the non-privileged execution mode using threads executed in the non-privileged execution mode.

12. The non-transitory computer readable medium of claim 11, wherein said conditions indicate allowable execution contexts using an execution level and a spin lock held indicator, said execution level indicating a runtime execution context level associated with said other code at a current execution point, said spin lock held indicator providing a runtime indication as to whether a spin lock is currently acquired at said current execution point.

13. The non-transitory computer readable medium of claim 12, wherein said execution level is set to one of a plurality of execution level values, said plurality of execution level values including a thread level, a deferred procedure call level and an interrupt level, said thread level indicating that said current execution point corresponds to a body of code associated with a thread or a deferred work item, said deferred procedure call level indicating that said current execution point corresponds to a body of code associated with a deferred procedure call or a timer, and said interrupt level indicating that said current execution point corresponds to a body of code associated with an interrupt service routine.

14. The non-transitory computer readable medium of claim 12, further comprising code for updating said execution level and said spin lock held indicator during execution of said other code to reflect a current runtime execution state of said other code.

15. The non-transitory computer readable medium of claim 12, wherein said execution level and said spin lock held indicator are examined prior to performing said requested operation to determine whether to perform said requested operation.

16. The non-transitory computer readable medium of claim 11, wherein each of said plurality of different platforms includes at least one of an operating system or hardware which is different from another of said plurality of different platforms.

17. The non-transitory computer readable medium of claim 11, wherein said application programming interface provides an interface to a code module stored on said non-transitory computer readable medium that:

performs said one or more operations when said other code executes in said non-privileged execution mode that is user mode; and

performs said one or more operations when said other code executes in said privileged execution mode that is kernel mode.

18. The non-transitory computer readable medium of claim 11, wherein said other code is allowed to be executed in a user mode that is said non-privileged execution mode and a kernel mode that is said privileged execution mode, and said requested one of said operations is performed in said user mode and said kernel mode in accordance with a same set of semantics so that runtime behavior exhibited when said requested one of said operations is performed while executing in said user mode is similar to runtime behavior exhibited when said requested one of said operations is performed while executing in said kernel mode.

19. The non-transitory computer readable medium of claim 11, wherein said scheduling and synchronization primitives perform operations on objects and said application programming interface includes one or more methods which perform said operations on said objects.

20. A non-transitory computer readable medium comprising code stored thereon for providing a set of one or more scheduling and synchronization primitives, the non-transitory computer readable medium comprising code stored thereon for:

providing an application programming interface for performing one or more operations, each of said one or more operations corresponding to one of said scheduling and synchronization primitives;

providing a set of one or more criteria indicating conditions as to when said scheduling and synchronization primitives are allowed to be performed, said conditions indicating allowable execution contexts using an execution level and a spin lock held indicator; and

determining, during execution of other code, whether to perform a requested one of said operations using said one or more criteria, said other code making a call using said application programming interface to perform said requested operation, said one or more criteria being determined in accordance with a plurality of different platforms so that said other code is portable to each of said different platforms, and wherein said other code is executing in one of a user mode or a kernel mode, and said requested operation is performed in said user mode if said other code is executing in said user mode and is performed in said kernel mode if said other code is executing in said kernel mode, said criteria including kernel-mode semantics for features of said kernel mode simulated when executing in said user mode, wherein first code of the application programming interface provides a same set of functionality for both the user mode and the kernel mode, said same set of functionality including functionality in connection with a deferred procedure call and an interrupt service routine, wherein the first code of the application programming interface simulates functionality in connection with any of a deferred procedure call executed in the user mode and an interrupt service routine executed in the user mode using threads executed in the user mode.