This is very interesting. It explains what I thought was an anomaly of the CA TriTune product, which we use here for profiling our in-house code. Strictly enforced standards here require inclusion of automatically customized code at the start of every COBOL procedure (main or subroutine) that DISPLAY's program name and version and compile date/time information at the first pass and bypasses the DISPLAY every other time using "ALTER ... GO TO" logic. The "ALTER ... GO TO" paragraphs now show up as serious hot spots in high-frequency subroutines where it never did before since we moved to z13 CEC's.
Many thanks for this investigation. Peter -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of David Crayford Sent: Friday, April 29, 2016 10:48 AM To: [email protected] Subject: Re: An explanation for branch performance? On 29/04/2016 10:34 PM, Joe Testa wrote: > There seems to be little point worrying about the time needed to branch past > an eyecatcher at the start of a program, compared to the time used by the > rest of the program. Unfortunately that's not true. For high frequency subroutines it can dominate the performance profile. We have customer feedback where the code has been profiled using APA and the hot spots are clearly at the branch over eye-cachers. The reason I'm asking the question is for a reason why? The customer suggested we were non re-entrant and saving registers into the instruction stream. Our code is re-entrant. -- This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
