> useful performance analysis requires years of experience with a platform, its software, the use of > appropriate measurement software, and considerable statistical prowess
True enough, but it's like if your house was on fire. I could tell you that firefighting takes specialized skills and years of experience. You'd still want to pull out the fire extinguisher and do your best. I'm not trying to take up a new consulting career; I am trying to answer one question, and I am the only guy to do it. I understand perfectly that CPU time is not everything, and typically has little relationship to wall clock time. John, as you know better than most, I have been in this racket *almost* as long as you have. But the question on the table today is CPU time. One more variable in here is that the 2094 is z/OS under VM -- I suspect that may affect the precision of z/OS's reported CPU times. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of John Gilmore Sent: Tuesday, July 17, 2012 8:36 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Help with elementary CPU speed question Rob Scott has pointed you in the right direction. Worth emphasizing is that CP-SU ratios are most useful for botionally 'scientific' , CP-intensive applications. Many 'business' applications are I/O-bound, some of them--MFUs are the classic example--to the extent that shrinking CP processing to zero has little measurable effect upon residence time. In I/O bound situations CP-SU ratios may be irrelevant or, worse, misleading. This old distinction is often lost sight of here because mainframe 'scientific' processing does not figure much in our discussions. It remains important. More generally, useful performance analysis requires years of experience with a platform, its software, the use of appropriate measurement software, and considerable statistical prowess. Absent this skill set, it is easy to make a fool of oneself and all but impossible to make useful contributions. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
