I know of a case where one specific COBOL application went to h*ll in a h*nd basket on z196 after performing satisfactorily for years on z10 and earlier. The problem turned out to be handling of MVCL, which this application was replete with. The problem was fixed in a microcode level that I would expect everyone to have by now.
. . JO.Skip Robinson SCE Infrastructure Technology Services Electric Dragon Team Paddler SHARE MVS Program Co-Manager 626-302-7535 Office 323-715-0595 Mobile [email protected] From: "Staller, Allan" <[email protected]> To: [email protected] Date: 07/14/2011 10:52 AM Subject: Re: Z196 Cobol pgm with higher CPU Sent by: IBM Mainframe Discussion List <[email protected]> My first thought is data proximity to instructions. That is data being modified within the width of the processor I-cache. The data modification will cause cache flush of the I-cache, and many processor cycles to re-establish the cache and various pipelines. This happened with SAS when the z/900 (?) processors came out. There should be a discussion in the archives about the SAS version of this issue. The solution is to move the data far enough away from the instructions so that the modification does not cause the cache to be flushed. HTH, <snip> Hello, We recently installed a Z196 and we have one COBOL DB2 program that is using twice the CPU time as before the new CPU. The program has not been recompiled and the data volume is the same. IBM has found nothing, yet. Strobe has not revealed any answers. All other programs use about 1/2 of the CPU time now. Any help would be greatly appreciated. </snip> ---------------------------------------------------------------------- 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
