Fix (APAR):  PK61306

Status:  Fix

Release:  6.1.0.9,6.1.0.7,6.1.0.5,6.1.0.3,6.1.0.2,6.1.0.13,6.1.0.11,6.1.0.1,6.1

Operating System:  AIX,HP-UX,Linux,Linux pSeries,Linux zSeries,Solaris,Windows,i5/OS,OS/400

Supersedes Fixes:

CMVC Defect:  xxxxxx

Byte size of APAR:  10476

Date: 2008-02-26

Abstract:  With large amounts of processing, unacceptable delays can be observed in the thread pooling code. Javacores show processing threads waiting to be notified in the BoundedBuffer.wait

Description/symptom of problem:
PK61306 resolves the following problem:

ERROR DESCRIPTION:
Thread dumps during these pauses like this for the Consumer
thread:

"Consumer : 14" (TID:0x3E153F00, sys_thread_t:0x3CD400E0,
state:CW, native ID:0x0008216F) prio=5
at java/lang/Object.wait
at java/lang/Object.wait
at com/ibm/ws/util/BoundedBuffer.waitGet_
at com/ibm/ws/util/BoundedBuffer.poll
at com/ibm/ws/util/ThreadPool.getTask
at com/ibm/ws/util/ThreadPool$Worker.run

LOCAL FIX:

PROBLEM SUMMARY

USERS AFFECTED:
IBM WebSphere Application Server version 6.1
users who are experiencing service
integration bus (SIB) processing delays.

PROBLEM DESCRIPTION:
With large amounts of processing,
unacceptable delays can be observed
in the thread pooling code.
Javacores show processing threads
waiting to be notified in the
BoundedBuffer.waitGet_ method.

RECOMMENDATION:
None

As a side effect of an optimization, threads in a thread pool
never wait indefinitely to be notified when a task is
submitted to a thread pool. As part of that optimization, the
logic used to determine whether or not a notification should
be sent depends on a race condition. Currently, an
unnecessarily large time window exists while checking that
condition, which can result in larger delays than intended for
some tasks submitted to the thread pool.

PROBLEM CONCLUSION:
The time window for the condition is significantly reduced,
which improves throughput.
The fix for this APAR is currently targeted for inclusion in
fix pack 6.1.0.17.
Please refer to the recommended updates page for delivery
information:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980


Directions to apply fix:
NOTE: Choose the:
1) Release the fix applies to
2) The Editions that apply
3) Delete the Editions & Methods that do not apply and this Note

Fix applies to Editions:
Release 6.0
__ Application Server (Express or BASE)
__ Network Deployment (ND)
__ WebSphere Business Integration Server Foundation (WBISF)
__ Edge Components
__ Developer
__ Extended Deployment (XD)

Install Fix to:
Method:
__ Application Server Nodes
__ Deployment Manager Nodes
__ Both

NOTE:
The user must:
* Have Administrative rights in Windows, or be the Actual Root User in a UNIX environments.
* Logged in with the same authority level when unpacking a fix, fix pack or refresh pack.
* Be at V6.0.2.2 or newer of the Update Installer. This can be checked by reviewing the level of the Update Installer in file <was_root>/updateinstaller/version.txt.

The Update Installer can be downloaded from the following link:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg21205991

For detailed instructions to Extract the Update Installer see the following Technote:
http://www-1.ibm.com/support/docview.wss?rs=180&uid=swg21205400

1) Copy PKxxxxx.pak file directly to the maintenance directory

2) Shutdown WebSphere
Manually execute setupCmdLine.bat in Windows or . ./setupCmdLine.sh in Unix from the WebSphere instance that maintenance is being applied to.

3) Launch Update Installer

4) Enter the installation location of the WebSphere product you want to update.

5) Select the "Install maintenance package" operation.

6) Enter the file name of the maintenance package to install (PKxxxxx.pak file which was copied in the maintenance directory).

7) Install the maintenance package.

8) Restart WebSphere

Directions to remove fix:
NOTE:
* The user must have Administrative rights in Windows, or be the Actual Root User in a UNIX environments.
* FIXES MUST BE REMOVED IN THE ORDER THEY WERE APPLIED
* DO NOT REMOVE A FIX UNLESS ALL FIXES APPLIED AFTER IT HAVE FIRST BEEN REMOVED
* YOU MAY REAPPLY ANY REMOVED FIX

Example: If your system has fix1, fix2, and fix3 applied in that order and fix2 is to be removed, fix3 must be removed first, fix2 removed, and fix3 re-applied.

1) Shutdown WebSphere
Manually execute setupCmdLine.bat in Windows or . ./setupCmdLine.sh in Unix from the WebSphere instance that uninstall is being run against.

2) Start Update Installer

3) Enter the installation location of the WebSphere product you want to remove the fix.

4) Select  "Uninstall maintenance package" operation.

5) Enter the file name of the maintenance package to uninstall (PKxxxxx.pak).

6) UnInstall maintenance package.

7) Restart WebSphere

Directions to re-apply fix:
1) Shutdown WebSphere.

2) Follow the Fix instructions to apply the fix.

3) Restart WebSphere.



Additional Information: