If you are running a lot of CICS regions, you might want to look at reducing the mastask values, my understanding is that WLM create's PB for every possible active task in CICS and they get scanned every 250 ms too.
On Mon, Mar 4, 2024 at 10:15 PM Jim Mulder <[email protected]> wrote: > The most important thing is RMPTTOM for reducing the SRM timer pop > overhead. > Note that Timer DIE processing is uncaptured time. > > My IEAOPTxx for running under VM has > > RMPTTOM=30000 /*REDUCE SRM INVOKATION FREQUENCY ON VM */ > > And that is a value we set a couple of decades ago, and haven't thought > much about it since. > You might want it even higher for faster machines than we had back then. > > I suggested some years ago that SRM should self-tune the timer pop > interval to be less frequent at low utilization, but I haven't gotten any > traction on that so far.. > > Jim Mulder > > > -----Original Message----- > From: IBM Mainframe Discussion List <[email protected]> On Behalf > Of Wendell Lovewell > Sent: Monday, March 4, 2024 6:08 PM > To: [email protected] > Subject: How to reduce the overhead of WLM? > > This is probably a strange question, but is there a way to reduce WLM cpu > usage? Here's the situation: > > - The system is a lightly used development system. Unless something is in > a loop (very rare), CPU % probably is usually less than 10%. And except > for system regions & CICS, it's rare to have multiple jobs running > concurrently. > - Only one processor defined to the VM. No ZIIP either. > - We are charged for CPU cycles. > - WLM is the highest consumer of CPU. JES2, TCPIP, ZFS and SDSFAUX round > out the top 5 consumers. > > There is a lot of information about WLM tuning, but as best I can tell > almost none of it relates to reducing WLM usage. > > From reading the Init & Tuning manual, I'm trying these settings: > AIMANAGEMENT=NO > HIPERDISPATCH=NO > CCCAWMT=450000 > RMPTTOM=15000 > > I was thinking that perhaps reducing whatever processing intervals I could > might help. But I can't tell these changes made a difference. (I don't > have a tool to measure WLM usage.) > > Any suggestions would be appreciated. > > TIA, > > Wendell > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send email > to [email protected] with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
