Synchronization objects for multi-computer systems

• US 7,058,948 B2
• Filed: 08/10/2001
• Issued: 06/06/2006
• Est. Priority Date: 08/10/2001
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Hoyle, Stephen L.
• Primary Examiner(s): Thomson, William
• Assistant Examiner(s): ANYA, CHARLES E
• Application Number:
  US09/928,115
• Publication Number:
  US 20030041173A1
• Time in Patent Office: 1,761 Days
• Field of Search: 718100-108, 711147-152, 711100-173, 709201-250, 710/200, 719/312, 707 1- 10, 707/201, 707/205
• US Class Current: 718/104
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database

Abstract

Several multiprocessor computer systems, each having its own copy of an operating system, are interconnected to form a multi-computer system having global memory accessible by any processor on any node and including provision for spinlock access control. In this environment, a global mutex, and other like synchronization objects, are realized that can control the coordination of multiple threads running on multiple processors and on multiple nodes or platforms. Each global mutex is supported by a local operating system shadow mutex on each node or platform where threads have opened access to the global mutex. Global mutex functionality is thus achieved that reflects and utilizes the local operating system'"'"'s mutex system.

Claims

1. A method for granting threads running on various multi-processor nodes within a multi-computer system ownership of a global synchronization object comprising the steps of:

maintaining a record of the state of the global synchronization object as free, owned, or in transition;

when a thread seeks ownership of the global synchronization object, granting the thread, through a spinlock mechanism, access to the status of the global synchronization object, and granting the thread ownership if the global synchronization object is free;

if the global synchronization object is owned or in transition, adding the thread'"'"'s node to a queue of nodes having threads awaiting ownership of the global synchronization object, and permitting the thread to seek ownership of a local synchronization object established on the thread'"'"'s node by a local operating system, but temporarily blocking other threads on the thread'"'"'s node from seeking ownership of the local synchronization object and forcing them into suspension;

when the global synchronization object ownership is released by a thread, placing the global synchronization object into its transition state, and then arranging for each node in the queue, in turn, to stop blocking threads on its node from seeking ownership of the local synchronization object, and permitting any thread that then gains ownership of its local synchronization object to resume execution and to gain ownership of the global synchronization object if the object is free or in transition, this process continuing until the global synchronization object is owned or until no more threads seek its ownership, at which point the global synchronization object enters its free state.

2. The method for granting threads running on various multi-processor nodes within a multi-computer system ownership of a global synchronization object in accordance with claim 1, wherein the local or global synchronization objects are mutexes.

3. The method for granting threads running on various multi-processor nodes within a multi-computer system ownership of a global synchronization object in accordance with claim 1, wherein the local or global synchronization objects are semaphores.

4. A set of synchronization software computer programs designed for use in conjunction with a multi-computer system, where individual nodes have their own copies of an operating system with local node synchronization software included in the operating system, said synchronization software computer programs being capable of carrying out the following steps to implement global synchronization objects:

maintaining a record of the state of each global synchronization object as free, owned, or in transition;

when a thread seeks ownership of a global synchronization object, granting the thread, through a spinlock mechanism, access to the status of the global synchronization object, and granting the thread ownership if the global synchronization object is free;

if the global synchronization object is owned or in transition, adding the thread'"'"'s node to a queue of nodes having threads awaiting ownership of the global synchronization object, and permitting the thread to seek ownership of a local synchronization object established on the thread'"'"'s node by a local operating system, but temporarily blocking other threads on the thread'"'"'s node from seeking ownership of the local synchronization object and forcing them into suspension;

when the global synchronization object ownership is released by a thread, placing the global synchronization object into its transition state, and then arranging for each node in the queue, in turn, to stop blocking threads on its node from seeking ownership of the local synchronization object, and permitting any thread that then gains ownership of its local synchronization object to resume execution and to gain ownership of the global synchronization object if the object is free or in transition, this process continuing until the global synchronization object is owned or until no more threads seek its ownership, at which point the global synchronization object enters its free state.

5. The set of synchronization software computer programs designed for use in conjunction with multi-computer system in accordance with claim 4, wherein the local or global synchronization objects are mutexes.

6. The set of synchronization software computer programs designed for use in conjunction with multi-computer system in accordance with claim 4, wherein the local or global synchronization objects are semaphores.