Lock optimization and lock prediction approaches for reducing client-server messages

• US 8,332,485 B1
• Filed: 03/04/2005
• Issued: 12/11/2012
• Est. Priority Date: 03/04/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Ben-Shaul, Israel Zvi, Zach, Idan, Glixman, Shahar, Lev-Ran, Etai
• Primary Examiner(s): Neurauter, George C
• Application Number:
  US11/073,046
• Time in Patent Office: 2,839 Days
• Field of Search: 707/8, 707/704, 710/200, 709202- 3, 709/219, 709/234, 709/235
• US Class Current: 709/219
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms

Abstract

Approaches are disclosed for lock optimization and lock prediction for reducing the number of client-server messages involved in working with server-based resources. First one or more lock requests for first one or more locks on a remote data resource that is linked by a slow communication link are received. Based on the first one or more lock requests, a sequence of lock requests for locks on the remote data resource is determined. A first message that includes the sequence of lock requests is sent. A second message is received. The second message includes second one or more locks on the remote data resource, where the second one or more locks correspond to second one or more lock requests of the sequence of lock requests. A particular lock of the second one or more locks is granted in response to receiving a particular lock request for the particular lock on the remote data resource.

Claims

1. A method, comprising the computer-implemented actions of:

receiving first one or more lock requests for first one or more locks on a remote data resource that is linked by a slow communication link;

based on the first one or more lock requests, determining a sequence of new lock requests for new locks, including a plurality of predicted locks, on the remote data resource;

sending a first message that includes the sequence of new lock requests;

receiving a second message that includes second one or more locks on the remote data resource, wherein the second one or more locks correspond to second one or more lock requests of the sequence of new lock requests;

storing the second one or more locks; and

granting a particular lock of the second one or more locks in response to receiving a particular lock request for the particular lock on the remote data resource.

2. The method as recited in claim 1, further comprising obtaining the second one or more locks on the remote data resource in response to receiving the first message at a remote server that holds the remote data resource.

3. The method as recited in claim 2, wherein:

the remote data resource is a file; and

obtaining the second one or more locks further comprises locking, for each lock of the second one or more locks, a range of bytes in the file.

4. The method as recited in claim 3, wherein the range of bytes comprises any one of a single byte, a plurality of bytes, and all bytes in the file.

5. The method as recited in claim 2, wherein obtaining the second one or more locks further comprises any one of obtaining all locks that are requested in the sequence of new lock requests and obtaining less than all locks that are requested in the sequence of new lock requests.

6. The method as recited in claim 1, further comprising sending a third message that includes one or more unlock requests to release any one of:

at least one lock of the first one or more locks, and

at least one lock of the second one or more locks.

7. The method as recited in claim 1, wherein the particular lock request for the particular lock is received after receiving the first one or more lock requests for the first one or more locks.

8. The method as recited in claim 1, further comprising receiving an unlock request to release the particular lock.

9. The method as recited in claim 1, wherein the remote data resource is a file managed by a file server that is communicatively connected to a remote server over a Local Area Network (LAN) connection, wherein the remote server is connected to the slow communication link.

10. The method as recited in claim 1, further comprising sending the first one or more lock requests for the first one or more locks to a local server from an application.

11. The method as recited in claim 10, wherein the application is executing on at least one of:

the local server; and

a client that is communicatively connected to the local server over a Local Area Network (LAN) connection.

12. The method as recited in claim 10, wherein:

sending the first one or more lock requests is performed in response to receiving, at the application, a user request to perform an operation on the remote data resource; and

the method further comprises performing the operation on the remote data resource.

13. The method as recited in claim 1, further comprising:

receiving a specific request for a specific lock on the remote data resource;

determining whether the specific lock is among the second one or more locks; and

if the specific lock is not among the second one or more locks, then sending a third message that includes one or more unlock requests to release any one of;

at least one lock of the first one or more locks, and

at least one lock of the second one or more locks.

14. The method as recited in claim 1, wherein determining the sequence of new lock requests further comprises predicting the sequence of new lock requests based on prior usage of the first one or more locks.

15. The method as recited in claim 14, wherein predicting the sequence of new lock requests further comprises automatically determining the prior usage of the first one or more locks based on trace files that store records indicating which locks were requested subsequently to prior requests for the first one or more locks.

16. The method as recited in claim 1, wherein the second one or more lock requests are a subset of the sequence of new lock requests.

17. The method as recited in claim 1, wherein the slow communication link is any one of a dial-up connection, a Wide Area Network (WAN) connection, a Digital Subscriber Line (DSL) connection, and an Integrated Services Digital Network (ISDN) connection.

18. A method of optimizing communication exchanges, the method comprising the computer-implemented actions of:

at a local server that is communicatively connected to a remote server over a slow communication link, receiving first one or more lock requests for first one or more locks on a remote data resource of the remote server;

based on the first one or more lock requests, determining a sequence of new lock requests for new locks, including plurality of predicted locks, on the remote data resource;

sending a first message to the remote server, wherein the first message includes the sequence of new lock requests;

receiving, from the remote server, a second message that includes second one or more locks on the remote data resource, wherein the second one or more locks correspond to second one or more lock requests of the sequence of new lock requests;

storing the second one or more locks at the local server; and

at the local server, granting a particular lock of the second one or more locks in response to receiving a particular lock request for the particular lock on the remote data resource.

19. The method as recited in claim 18, further comprising sending, to the remote server, a third message that includes one or more unlock requests to release any one of:

at least one lock of the first one or more locks, and

at least one lock of the second one or more locks.

20. The method as recited in claim 18, further comprising releasing the particular lock of the second one or more locks in response to receiving an unlock request to release the particular lock.

21. A system for optimizing communication exchanges, the system comprising:

a remote server that is communicatively connected to a file server over a Local Area Network (LAN) connection, wherein the file server manages a remote data resource;

a local server that is communicatively connected to the remote server over a Wide Area Network (WAN) communication link, wherein the local server comprises;

one or more processors; and

one or more stored sequences of instructions, which instructions, when executed by the one or more processors, cause the one or more processors to perform the actions of;

receiving first one or more lock requests for first one or more locks on the remote data resource;

based on the first one or more lock requests, determining a sequence of new lock requests for new locks, including a plurality of predicted locks, on the remote data resource;

sending a first message to the remote server, wherein the first message includes the sequence of new lock requests;

receiving, from the remote server, a second message that includes second one or more locks on the remote data resource, wherein;

the remote server has obtained the second one or more locks from the file server; and

the second one or more locks correspond to second one or more lock requests of the sequence of new lock requests;

storing the second one or more locks; and

granting a particular lock of the second one or more locks in response to receiving a particular lock request for the particular lock on the remote data resource.

22. An apparatus, comprising:

receiving means for receiving first one or more lock requests for first one or more locks on a remote data resource that is linked by a slow communication link;

determining means for determining, based on the first one or more lock requests, a sequence of new lock requests for new locks, including a plurality of predicted locks, on the remote data resource;

sending means for sending a first message that includes the sequence of new lock requests;

second receiving means for receiving a second message that includes second one or more locks on the remote data resource, wherein the second one or more locks correspond to second one or more lock requests of the sequence of new lock requests;

storing means for storing the second one or more locks; and

granting means for granting a particular lock of the second one or more locks in response to receiving a particular lock request for the particular lock on the remote data resource.

23. The apparatus of claim 22, wherein:

the remote data resource is a file; and

each lock of the second one or more locks comprises a locked range of bytes in the file, wherein the locked range of bytes comprises any one of a single byte, a plurality of bytes, and all bytes in the file.

24. The apparatus of claim 22, further comprising second sending means for sending a third message that includes one or more unlock requests to release any one of:

at least one lock of the first one or more locks, and at least one lock of the second one or more locks.

25. The apparatus of claim 22, further comprising third receiving means for receiving an unlock request to release the particular lock.

26. The apparatus of claim 22, further comprising:

third receiving means for receiving a specific request for a specific lock on the remote data resource;

determination means for determining whether the specific lock is among the second one or more locks; and

second sending means for sending a third message that includes one or more unlock requests to release any one of;

at least one lock of the first one or more locks, and

at least one lock of the second one or more locks.

27. An apparatus, comprising:

one or more processors;

one or more storage devices storing one or more sequences of instructions, which the instructions, when executed by the one or more processors, cause the one or more processors to perform the actions of;

receiving first one or more lock requests for first one or more locks on a remote data resource that is linked by a slow communication link;

based on the first one or more lock requests, determining a sequence of new lock requests for new locks, including a plurality of predicted locks, on the remote data resource;

sending a first message that includes the sequence of new lock requests;

receiving a second message that includes second one or more locks on the remote data resource, wherein the second one or more locks correspond to second one or more lock requests of the sequence of new lock requests;

storing the second one or more locks; and

granting a particular lock of the second one or more locks in response to receiving a particular lock request for the particular lock on the remote data resource.

28. The apparatus of claim 27, wherein:

the remote data resource is a file; and

each lock of the second one or more locks comprises a locked range of bytes in the file, wherein the locked range of bytes comprises any one of a single byte, a plurality of bytes, and all bytes in the file.

29. The apparatus of claim 27, wherein the instructions cause the one or more processors to perform the action of sending a third message that includes one or more unlock requests to release any one of:

at least one lock of the first one or more locks, and

at least one lock of the second one or more locks.

30. The apparatus of claim 27, wherein the instructions cause the one or more processors to perform the action of receiving an unlock request to release the particular lock.

31. The apparatus of claim 27, wherein the instructions cause the one or more processors to receive the first one or more lock requests for the first one or more locks from an application.

32. The apparatus of claim 27, wherein the instructions further cause the one or more processors to perform the actions of:

receiving a specific request for a specific lock on the remote data resource;

determining whether the specific lock is among the second one or more locks; and

if the specific lock is not among the second one or more locks, then sending a third message that includes one or more unlock requests to release any one of;

at least one lock of the first one or more locks, and

at least one lock of the second one or more locks.

33. The apparatus of claim 27, wherein the instructions causing the one or more processors to perform the action of determining the sequence of new lock requests further cause the one or more processors to perform the step of predicting the sequence of new lock requests based on prior usage of the first one or more locks.

34. The apparatus of claim 33, wherein the instructions causing the one or more processors to perform the action of predicting the sequence of new lock requests further cause the one or more processors to perform the step of determining the prior usage of the first one or more locks based on trace files that store records indicating which locks were requested subsequently to prior requests for the first one or more locks.

35. A computer-readable storage device storing one or more sequences of instructions, which instructions, when executed by one or more processors, cause the one or more processors to perform the actions of:

receiving first one or more lock requests for first one or more locks on a remote data resource that is linked by a slow communication link;

based on the first one or more lock requests, determining a sequence of new lock requests for new locks, including a plurality of predicted locks, on the remote data resource;

sending a first message that includes the sequence of new lock requests;

receiving a second message that includes second one or more locks on the remote data resource, wherein the second one or more locks correspond to second one or more lock requests of the sequence of new lock requests;

storing the second one or more locks; and

granting a particular lock of the second one or more locks in response to receiving a particular lock request for the particular lock on the remote data resource.