WebSphere Application Server traces can be extremely helpful in detecting and diagnosing problems.
By properly setting trace options, you can capture the information needed to detect problems without significant performance overhead.
You should check your WebSphere for z/OS tracing options to ensure that ras_trace_defaultTracingLevel=0 or 1, and that ras_trace_basic and ras_trace_detail are not set.
If you are tracing to sysprint with ras_trace_defaultTracingLevel=3, you may experience an almost 100% throughput degradation. If you are tracing to CTRACE, however, you may only experience a 15% degradation in throughput.
This will get 512KB of storage for the trace buffers (the minimum allowed) and reduce memory requirements.
com.ibm.ejs.*=all=disable com.ibm.ws390.orb=all=disableEnsure that both lines are set to =disable or delete the two lines altogether.