Method and system for tracing profiling information using per thread metric variables with reused kernel threads

• US 7,389,497 B1
• Filed: 07/06/2000
• Issued: 06/17/2008
• Est. Priority Date: 07/06/2000
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Levine, Frank Eliot, Urquhart, Robert J., Edmark, Ronald O'Neal
• Primary Examiner(s): Dam; Tuan
• Assistant Examiner(s): KENDALL, CHUCK O
• Application Number:
  US09/612,350
• Time in Patent Office: 2,903 Days
• Field of Search: 717/127, 717/128, 717/130, 717/137, 717/158, 717/131
• US Class Current: 717/130
• CPC Class Codes: G06F 11/3612 by runtime analysis performance monitoring G06F11/3466

Abstract

A method and system for tracing profiling information using per thread metric variables with reused kernel threads is disclosed. In one embodiment kernel thread level metrics are stored by the operating system kernel. A profiler request metric information for the operating system kernel in response to an event. After the kernel thread level metrics are read by the operating system for a profiler, their values are reset to zero by the operating system kernel. The profiler then applies the metric values to base metric values to appropriate Java threads that are stored in nodes in a tree structure base on the type of event and whether or not the kernel thread has been reused. In another embodiment non-zero values of thread level metrics are entered on a liked list. In response to a request from a profiler, the operating system kernel reads each kernel thread'"'"'s entry in the linked list and zeros each entry. The profiler can then update the intermediate full tree snapshots of profiling information with the collection of non-zero metric variables.

Claims

1. A method for monitoring performance of a program being executed using per thread metric variables with reused kernel threads comprising:

receiving an event indication;

ascertaining kernel thread level profile information;

identifying a kernel thread, wherein the kernel thread level profile information is attributed to the identified kernel thread;

determining whether the identified kernel thread has been reused; and

updating profile information with the kernel thread level profile information based whether the identified kernel thread has been reused.

2. The method recited in claim 1 above, wherein determining whether the identified kernel thread has been reused further comprises:

checking a hash table for an entry of the identified kernel thread.

3. The method recited in claim 1 above, wherein updating profile information with the kernel thread level profile information based on the identified kernel thread is reused further comprises:

applying the kernel thread level profile information for the reused identified kernel thread to one of a previous application thread and a new application thread.

4. The method recited in claim 2 above, wherein updating profile information with the kernel thread level profile information based on the identified kernel thread is reused further comprises:

applying the kernel thread level profile information for the reused identified kernel thread to one of a previous application thread and a new application thread;

marking the previous application thread being terminated; and

associating the reused identified kernel thread with the new application thread in the hash table.

5. The method recited in claim 1 above, wherein the profile information is stored in a node for a application thread which is associated with the kernel thread level profile information.

6. The method recited in claim 1 above, wherein ascertaining kernel thread level profile information further comprises:

sending a request for kernel thread level profile information to an operating system kernel, wherein the operating system kernel responds to the request by;

receiving the request for kernel thread level profile information;

accessing a processor data area containing processor level accumulated profile information;

calculating a change in processor level accumulated profile information;

accessing kernel thread level profile information held by the operating system kernel;

updating kernel thread level profile information held by the operating system kernel with the change in processor level accumulated profile information; and

sending the kernel thread level profile information held by the operating system kernel to a requestor.

7. The method recited in claim 5 above further comprises:

resetting the kernel thread level profile information held by the operating system kernel.

8. The method recited in claim 1 above, wherein updating profile information with the kernel thread level profile information based whether the identified kernel thread has been reused further comprises:

updating an information area for a current application thread based on the identified kernel thread having not been reused.

9. The method recited in claim 1 above, wherein updating profile information with the kernel thread level profile information based whether the identified kernel thread has been reused further comprises:

updating an information area for a previous application thread based on the identified kernel thread having been reused.

10. The method recited in claim 1 above, wherein updating profile information with the kernel thread level profile information based whether the identified kernel thread has been reused further comprises:

accessing an information area for a application thread based on the identified kernel thread;

updating an information area for the application thread.

11. The method recited in claim 3 above, wherein the application is a Java application.

12. A method for monitoring performance of a program being executed using per thread metric variables with reused kernel threads comprising:

receiving a value of a metric variable for a kernel thread;

determining if the kernel thread has been previously used by a first application thread; and

applying the value of the metric variable to a second application thread if the kernel thread has been previously used by the first application thread.

13. The method recited in claim 12 above, further comprises:

identifying the first application thread as being terminated based on the kernel thread having been previously used by the first application thread.

14. The method recited in claim 12 above, wherein the first application thread is a current application thread based on the kernel thread having not been used.

15. The method recited in claim 12 above, wherein determining if the kernel thread has been previously used by the first application thread further comprises:

comparing an identity of the kernel thread to a list of identities of previously used kernel threads.

16. The method recited in claim 12 above, wherein the value of a metric variable for a kernel thread is a change in value of the metric variable since the last receipt of the metric variable for the kernel thread.

17. The method recited in claim 12 above, wherein the metric variable relates to one of allocation bytes, allocation objects, time, live object and live bytes.

18. The method of claim 12, wherein the value of the metric variable for the kernal thread is received in response to an event occuring based on the execution of the second application thread.

19. The method of claim 12, wherein applying the value of the metric variable to the second application thread in a node associated with the second application thread by an amount equal to the value of the metric variable.

20. A method for monitoring performance of a program being executed using per thread metric variables with reused kernel threads comprising:

receiving a plurality of values of metric variables for a plurality of kernel threads;

for each kernel thread;

determining if a kernel thread has been previously used by a prior application thread; and

applying the value of the metric variable for the kernel thread to a current application thread if the kernel thread has been previously used by a prior application thread.

21. The method recited in claim 20 above, wherein the plurality of values of metric variables for a plurality of kernel threads are received from an operating system kernel wherein each of the plurality of values was contained in a linked list of entries, each entry in the linked list being a value of a metric variable for a specific kernel thread.