This was also discussed at the zSeries EXPO in Orlando (10/9-13). IIRC Kathy Walsh discussed it in the z/OS Performance Hot Topics. It's all a little fuzzy but I believe there was a strong recommendation to set RMPTTOM to 2000 on any z9 and even z890/990 boxes. Possible benefit to playing with higher values in the 3-10k range. IIRC there was little if any downside in the 2-5k range although you should monitor and keep an eye on period switching.
The pdf in the link explains it reasonably well I thought. Ken Porowski AVP Systems Software CIT Group E: [EMAIL PROTECTED] -----Original Message----- Jason Gately Yes....we set it to 2000 last week, and saw a reduction in Uncaptured. (in fact, this APAR was created in part due to some excellent work by our capacity & performance guy's, who saw a marked increase in Uncaptured when we recently went to z9's, and wouldn't accept IBM's answer that it was WAD). Cheers...Jason. Richards.Bob http://www-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/FLASH10526 Anyone else with z9EC boxes catch this flash out on Techdocs and try the workaround yet? For now, it conditionally recommends adding the RMPTTOM keyword with a value of 2000 to the IEAOPTxx member (wherever you have it in your PARMLIB concatenation). See abstract below: Abstract: z/OS Performance on IBM System z9 has reported a drop in z/OS capture ratio after migration to a 2094 EC processor. The impact on capture ratio has been traced to the frequency of SRM timer intervals. This flash describes findings regarding the SRM timer interval and its possible impact on captured time. The flash provides information and recommendations for z/OS tuning. Bob Richards VP, Enterprise Technologist Suntrust Banks, Inc (404) 575-2798 [EMAIL PROTECTED] Seeing beyond money (sm) ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
