My comments about 1. A million times a second... etc Were from about 30 years ago, before optimization improved.
I know that the "hot" instruction for MQ on z/OS that showed up in profiling, was the Load/Update Address of the next free slot in the trace buffer in ECSA. When there were many concurrent threads using MQ trace, they all used this field. Sometimes the field was on the same chip. Sometimes it was in a different "book" (and so the time to get this field was 1000 times the duration if it was in the same CPU) By giving each TCB its own trace buffer this hotspot disappeared! The compiler could not optimize this. Only a change of design could fix it. Colin ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
