Snapshot interface operations

• US 20060059282A1
• Filed: 12/20/2004
• Published: 03/16/2006
• Est. Priority Date: 08/30/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Govindaraju, Rama K., Hochschild, Peter H., Hong, Deryck X., Chaudhary, Piyush, Houston, John S., Martin, Steven J., Goscinski, Jason E., Helmer, Leonard W. Jr., Lee, Jang-Soo, Zhu, Yuqing
• Granted Patent: US 8,364,849 B2
• Time in Patent Office: Days
• US Class Current: 710/100
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

In a multinode data processing system in which the nodes communicate with one another via communication adapters over a network or switch, the adapters are provided with a dual register mechanism for tracking microcode task status. Upon the issuance of a disruptive command that requires attention from one of the nodes, the task status maintained in one register is copied to the snapshot register. As tasks within the adapter are completed, both registers are updated, thus providing a mechanism for the nodes to determine that all tasks active at the time of the disruptive command have completed. This means that the nodes now have a mechanism for determining, as soon as possible, that all tasks that are active when a disruptive command occurs have completed, thus allowing the data processing node to perform such operations as releasing system memory that is associated with the disruptive command, thus eliminating temporal overhead that can affect performance.

Claims

1. A method for operating a communications adapter having microcode control, said method comprising the steps of:

upon starting microcode tasks in said adapter, setting a bit corresponding to said task in an adapter state register;

upon issuance of a disruptive command to said adapter, copying said state register to a snapshot register;

upon completing microcode tasks in said adapter, clearing said bit corresponding to said task in said adapter state register and in said snapshot register; and

querying said snapshot register.

2. The method of claim 1 in which said querying is carried out by a data processing node coupled to said adapter.

3. The method of claim 2 in which said querying is carried out periodically by said data processing node.

4. The method of claim 2 in which said data processing node determines from said query that all tasks that were active at the time of the disruptive command have completed operations in progress at the time of the disruptive command.

5. The method of claim 1 in which said disruptive command is a close window command.

6. A method for operating a communications adapter, said method comprising the steps of:

tracking active tasks in a first register and in a second register;

transferring said first register to said second register upon issuance of a disruptive command to said adapter; and

updating said second register to indicate tasks completed after said disruptive command.

7. The method of claim 6 further including querying said second register.

8. The method of claim 7 in which said query is to determine what tasks are still active subsequent to the issuance of said disruptive command.

9. The method of claim 6 in which said disruptive command is a close window command.

10. The method of claim 7 in which said querying is carried out by a data processing node coupled to said adapter.

11. The method of claim 10 in which said querying is carried out periodically by said data processing node.

12. The method of claim 10 in which said data processing node determines from said query that all tasks that were active at the time of said disruptive command have completed operations in progress at the time of said disruptive command.

13. A multinode data processing system comprising:

a plurality of data processing nodes together with a respective plurality of communications adapters coupled thereto which enable said nodes to communicate through a switch or network to which said adapters are coupled; and

programming within said adapter that, upon starting microcode tasks in said adapter, sets a bit corresponding to said task in an adapter state register, and upon issuance of a disruptive command to said adapter, copying said state register to a snapshot register and, upon completing microcode tasks in said adapter, clearing said bit corresponding to said task in said adapter state register and in said snapshot register.

14. The system of claim 13 in which at least one of said nodes includes programming for querying said snapshot register.