Chapter 9. WebSphere Application Server
149
9.1.3 Performance
When you run WebSphere Application Server on IBM POWER7 Systems, the end-to-end
performance depends on many subsystems. The subsystems include network, memory, disk,
and CPU subsystems of POWER7; a crucial consideration is Java configuration and tuning.
Topology also plays a major role in the performance of the enterprise application that is being
deployed. The architecture of the application must be considered when you determine the
best deployment topology. Table 9-3 includes links to preferred practices documents, which
target each of these major areas.
Table 9-3 Performance considerations
WebSphere channel framework degradation on POWER7
Certain applications that run on WebSphere Application Server on POWER7 can experience
performance degradation because of asynchronous I/O (AIO). AIO can be disabled to
improve the performance of these applications. For instructions about how to accomplish this
task, see Disabling AIO (Asynchronous Input/Output) native transport in WebSphere
Application Server, available at:
http://www.ibm.com/support/docview.wss?uid=swg21366862
Scalability challenges when moving from POWER5 or POWER6 to
POWER7
By default, POWER7 runs in SMT4 mode. As such, there are four hardware threads (or four
logical CPUs) per core that provide tremendous concurrency for applications. If the enterprise
applications are migrated to POWER7 from an earlier version of POWER hardware
(POWER5 or POWER6), you might experience scalability issues because the default SMT
mode on POWER7 is SMT4, but on POWER5 and POWER6, the default is SMT and SMT2
mode. As some of these applications might not be designed for the massive parallelism of
POWER7, performance and scalability can be improved by using smaller partitions or
processor binding. Processor binding is described in “Processor affinity benefits for
WebSphere applications” on page 150.
Consideration
Associated website
Information provided
Java Performance on
POWER7 - Best practices
http://public.dhe.ibm.com/c
ommon/ssi/ecm/en/pow03066us
en/POW03066USEN.PDF
This white paper highlights key
preferred practices for all Java
applications that are running on
Power Systems and SMT
considerations when you are
migrating from POWER 5 or 6 to
POWER7.
Optimizing AIX 7 network
performance: Part 1,
Network overview -
Monitoring the hardware
http://www.ibm.com/develope
rworks/aix/library/au-aix7n
etworkoptimize1/index.html
This three-part white paper
reviews AIX V7.1 networking and
includes suggestions for
achieving the best network
performance.
Optimizing AIX V7 memory
performance: Part 1,
Memory overview and tuning
memory parameters
http://www.ibm.com/develope
rworks/aix/library/au-aix7m
emoryoptimize1/index.html
Memory optimization is essential
for running WebSphere
Application Server faster on
POWER7.
Optimizing AIX V7
performance: Part 2,
Monitoring logical volumes
and analyzing the results
http://www.ibm.com/develope
rworks/aix/library/au-aix7o
ptimize2/index.html
Optimizing the disk and
troubleshooting the I/O
bottlenecks is crucial for
I/O-intensive applications.
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