Performance Analysis, Problem Determination, And Diagnostic Tests - IBM Power7 Optimization And Tuning Manual

Processor affinity benefits for WebSphere applications
When an application is running on top of WebSphere Application Server is deployed on a
large LPAR, it might not use all the cores in that LPAR, resulting in less than optimum
application performance. If this situation occurs, performance improvements to these
applications can be obtained by binding the application server to certain cores. This task can
be accomplished by creating the resource sets and attaching them to the application server
that is running excerset. For an example of using the taskset and numactl commands in a
Linux environment, see "Partition sizes and affinity" on page 14.
Memory affinity benefits for WebSphere applications
In addition to the processor affinity described in "Processor affinity benefits for WebSphere
applications", applications can benefit from avoiding remote memory accesses by setting the
environment variable MEMORY_AFFINITY to MCM. This variable allocates application private and
shared memory from processor local memory.
These three tuning techniques (SMT scalability, CPU affinity, and memory affinity) can
improve the performance of WebSphere Application Server on POWER7 Systems. For an
example of using the taskset and numactl commands in a Linux environment, see "Partition
sizes and affinity" on page 14.
More information about these topics is in Java Performance on POWER7 - Best practices,
found at:
http://public.dhe.ibm.com/common/ssi/ecm/en/pow03066usen/POW03066USEN.PDF

9.1.4 Performance analysis, problem determination, and diagnostic tests

Resources for addressing issues regarding performance analysis, problem determination,
and diagnostic tests are listed in Table 9-4.
Table 9-4 Performance analysis and problem determination
Consideration
Java Performance Advisor
The performance detective:
Where does it hurt?
MustGather: Performance,
hang, or high CPU issues
with WebSphere Application
Server on AIX
150
POWER7 and POWER7+ Optimization and Tuning Guide
Associated website
https://www.ibm.com/develop
erworks/wikis/display/WikiP
type/Java+Performance+Advis
or
http://www.ibm.com/develope
rworks/aix/library/au-perfo
rmancedectective/index.html
http://www.ibm.com/support/
docview.wss?uid=swg21052641
Information provided
The Java Performance Advisor
(JPA) tool provides suggestions
for improving the performance of
Java/WebSphere Application
Server applications that are
running on Power Systems.
Describes how to isolate
performance problems.
MustGather assists with
collecting the data necessary to
diagnose and resolve issues with
hanging or CPU usage issues.