Method of conducting asynchronous distributed collective operations

• US 5,748,959 A
• Filed: 05/24/1996
• Issued: 05/05/1998
• Est. Priority Date: 05/24/1996
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Reynolds, David Corder
• Primary Examiner(s): TOPLU, LUCIEN
• Application Number:
  US08/653,559
• Time in Patent Office: 711 Days
• Field of Search: 395/670, 395/676, 395/682, 395/326, 395/702
• US Class Current: 718/106
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

A method and apparatus for distributing data in a multiprocessing system having a plurality of nodes. Each node has a user application for issuing a blocking or a non-blocking command. A request handle identifies each non-blocking command, while being set to a null value when in blocking mode.

For each requested command issued by any of the user applications, a report is generated comprising of data structures, for recording the sequence of functions to be executed asynchronously given a non-blocking command. Blocking commands are processed synchronously. Once the report is generated the sequence of functions recorded in the report are executed in the sequence presented in the report. However, whenever an internal dependency is encountered the control is returned to user application until the internal dependency is resolved. Upon completion of requested command, the user application is notified.

Claims

1. In a multiprocessor system having multiple nodes, a method of distributing data from a first node to at least a second node using request commands, each node having a user application for issuing said request command, said method comprising the steps of:

assigning a handle for identifying a command, said handle being set to a value for non-blocking mode and to null for blocking mode;

processing a requested non-blocking command when said handle is assigned a value in said assigning step;

building a report for recording a sequence of functions to be executed asynchronously given said non-blocking command;

executing in order, the sequence of functions recorded in said report;

when reaching a function that cannot be executed due to an internal dependency which requires some other operation to be completed before execution, returning control to said user application whereby said user application may perform other, unrelated operations; and

providing a handler routine to notify said user application when said internal dependency is resolved and removing said control away from said user application to continue with executing said requested non-blocking command.

2. The method of claim 1, further comprising the step of informing said user application when said requested non-blocking command is completed.

3. The method of claim 1, further comprising the step of processing said functions synchronously when said request handle is set to a null value, indicating a blocking mode.

4. The method of claim 1, wherein said report comprises at least one data structure.

5. The method of claim 4, wherein said command involves processing a plurality of tasks and said report creates one data structure per task to be performed.

6. The method of claim 1, wherein said internal dependency can be a blocking command.

7. The method of claim 1, wherein said control is returned to said user application by the steps of:

causing a hardware interrupt;

sending a message to said user application notifying said user application of said dependency; and

continuing with resolving said internal dependency while allowing said user application to commence other activities.

8. The method of claim 1, wherein said user application is notified that said internal dependency is resolved by causing a hardware interrupt to occur;

and sending a message to said user application notifying said user application that said dependency has been resolved.

9. The method of claim 8, further comprising the step of asking said user application as whether to remove control from said application to continue with said requested command.

10. The method of claim 8 further comprising the step of allowing said user application to continue maintaining said control but storing any information related to said requested command so that said processing of said requested command can be reinitiated at a later time and upon return of control by said user application.

11. The method of claim 1 further comprising the step of processing a new request, wherein said new request involves a request for traversing any previously performed operation(s) using said sequence noted in said report.

12. The method of claim 5 further comprising the step of processing a new request, wherein said new request involves traversing a previously performed operation(s) using said sequence noted in said report.

13. The method of claim 12 said new request is processed by traversing said entry steps in said data structure or data structures one step at a time.