The past few weeks meeting with various WebSphere Application Server-based customers reminded me of the importance of the basic and fundamental performance tuning tasks. The InfoCenter provides information on tunings at the OS level, TCP/IP, JVM, etc. I have visited no less than 3 different environments running WebSphere Application Server without these base tunings. Just by applying the base tunings to the OS and JVM we saw as much as 99% less garbage collection, improved response time, throughput and less CPU utilization with the same production loads. The best part of following these instructions is the administrator does not need to be a performance guru to realize these gains. These improvements also help save money requiring less capacity going forward.
Links to the v6.1
"Tuning Performance" in the InfoCenter
In the "Tuning the JVM" section I have never been disappointed with the "Option 1" settings. Options 2 and 3 require the ability to place the application under load/stress test. If you do not have a load/stress test environment (i.e. you have to test in production) then stick with "Option 1".
Notice that "Tuning Performance" has several sections for both application developers and WebSphere administrators. This is because we all know that to realize the best performance gains one has to optimize the application code. Runtime tuning can realize 5-15% but application code improvements can see 300% and higher performance improvements.