Comments interspersed. From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Klein, Kenneth E Sent: Wednesday, May 14, 2014 3:36 PM To: [email protected] Subject: supervisor state vs. problem state
What is the general opinion out there on what portion of CPU cycles should be spent in supervisor state? Is more than 50% a "bad thing"? ---> See my previous reply to Gil. I would consider this a bad thing on a z/OS box. On an *IX box, not necessarily. The beans are counted differently and stuff that z/OS charges back to a user, *IX boxes just account for as "overhead" (i.e. supervisor state). The RMF workload activity report should be able to give you some help here. Could having a logical processor to physical processor ratio of greater than 2 (e.g. 8 logicals in a 3 CP cec) be "bad"? ---> PR/SM overhead grows dramatically after 3:1 logical to physical. CPU times increase due to cache flushing in the processor (aka context switching). Your comment above equates to 2.67:1 I have run for several years with a 3:1 with minimal issues IMO, the 2.67 to 1 is "OK". YMMV. What is a reasonable rate for SIGP (Signal processor) instructions? Our rate is in the thousands. ---> Don't know. The most probable answer is "it depends". IO configuration, processor enablement for IO interrupts. Logical to physical processors,... all have a role to play HTH, ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
