Ed, Thank you for the response. I doubt paging would be an issue on this machine. The user did not report back on elapsed times. I suspect when he saw the charges for the job had doubled, elapsed time took secondary importance.
________________________________ From: Edward Jaffe [mailto:[EMAIL PROTECTED] Sent: Mon 5/12/2008 1:00 PM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: Question concerning performance, VIO and chargeback O'Brien, David W. (NIH/CIT) [C] wrote: > We are running Z/os 1.7. It recently came to my attention that VIO had been > implemented in such a way that temp datasets no matter how small ALWAYS went > to DASD. One of my predessesors used a storclas with Guaranteed Space. Anyway > a user asked to be able to use VIO so I turned it on. Today he comes back > with test results showing higher chargeback for CPU when using VIO. My > question is - How is this possible? > > We are processing the same numbers of records and eliminating some physical > I/O and the CPU usage is higher. > The total CPU for the job doubled. I would have thought that eliminating some > of the channel activity would have reduced CPU usage. Can someone explain > this to me? > VIO is CKD DASD emulated by software. Some processing that would normally be "offloaded" to the DASD controller is now being done by software running on general CPs, the storage occupied by the emulated file will need to be paged in/out, etc. Do you get better elapsed times? -- Edward E Jaffe Phoenix Software International, Inc 5200 W Century Blvd, Suite 800 Los Angeles, CA 90045 310-338-0400 x318 [EMAIL PROTECTED] http://www.phoenixsoftware.com/ ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- 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
