On Thu, 15 Nov 2012 13:56:43 -0500, Jim Mulder <[email protected]> wrote:
>One of the CPU designers gave me the following explanation: > >System z processor development has identified an aspect of >the z196 processor that performs worse than the equivalent >instruction on a z10 processor. When an SPKA instruction is >executed in problem state, the new out-of-order design of the >z196 processor requires more pipeline stalls to give >functionally correct results than in prior generations of >processors. > >Therefore, on workloads (i.e. CICS running with STGPROT=YES) >that have an intense amount of SPKAs in problem state, this >can show up as the z196 spending more time executing the SPKA >instruction. Some vendor performance tools or single instruction >benchmarks may uncover this additional time spent on the SPKA >instruction. This change in SPKA behavior does not >offset the benefits the z196 provides for the CICS environment. >This aspect of the longer SPKA execution time can be exacerbated >by running on a subcapacity machine. > > My client was able to see the difference, especially in a particular vendor's CICS monitor. Although according to the vendor, what was seen via Strobe was not completely accurate. There were changes made to CICS remove unnecessary SPKAs but the monitor's code had none that could be removed. -- Mark Zelden - Zelden Consulting Services - z/OS, OS/390 and MVS mailto:[email protected] Mark's MVS Utilities: http://www.mzelden.com/mvsutil.html Systems Programming expert at http://expertanswercenter.techtarget.com/ ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
