Example of what Barry is saying: For QSAM EXCP is number of blocks transferred. Buffering can make this much greater than the I/O count. The latter is best seen in SMF 42-6.
Cheers, Martin Martin Packer, zChampion, Principal Systems Investigator, Worldwide Cloud & Systems Performance, IBM +44-7802-245-584 email: [email protected] Twitter / Facebook IDs: MartinPacker Blog: https://www.ibm.com/developerworks/mydeveloperworks/blogs/MartinPacker Podcast Series (With Marna Walle): https://developer.ibm.com/tv/mpt/ or https://itunes.apple.com/gb/podcast/mainframe-performance-topics/id1127943573?mt=2 From: "Nims,Alva John (Al)" <[email protected]> To: [email protected] Date: 25/09/2017 15:57 Subject: Re: SMF30 EXCP count confusion Sent by: IBM Mainframe Discussion List <[email protected]> This is off the top-of-my-head (not much left anymore), but I believe 1 EXCP can do multiple blocks, as in the number of "Buffers" defined for the I/O so if multiple blocks have been queued into a single buffer, the buffer would be written by one EXCP, maybe, I think. Al Nims Systems Admin/Programmer 3 UFIT University of Florida (352) 273-1298 -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Peter Hunkeler Sent: Monday, September 25, 2017 10:16 AM To: [email protected] Subject: SMF30 EXCP count confusion SMF manual, Chapter 10 "EXCP Count" seems to clearly state that EXCP counts are indeed the number of EXCPs executed. Fields SMF30TEP and SMF30TEX are described as "Total blocks transferred (accumulated EXCP counts). I would assume that these fields still contain the number of EXCPs executed and not the number of blocks transferred. IMHO, the number of blocks is greater or equal to number of EXCPs. So, the number of EXCPs is only a relative measure of the I/O done when comparing multiple runs of the same program using the same I/O attributes (blocksize, bufno, etc. etc). It is not a direct measure of the abount of data really transferred. Am I right, or what am I missing? -- Peter Hunkeler ---------------------------------------------------------------------- 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 Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
