I really like ICSF (having worked on it for over 25 years), but I will say this right now: address-space-switch PCs are not cheap.
Trying to shave a handful of instructions to call ICSF is not going to save enough cycles (or elapsed time) to be worthwhile. As Colin points out, storage management will help quite a bit usually. I would suggest that you focus on your application and find the hot spots in it first and see if the pain of trying to rework your crypto calls is worth it. Eric Rossman -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Colin Paice Sent: Sunday, January 14, 2024 1:07 PM To: [email protected] Subject: [EXTERNAL] Re: Direct branch entry to ICSF routines Is this to reduce the elapsed time, or that you are doing this a million times a second and want to save CPU? I expect any elapsed time impact is going to be at the sub microsecond level. I would have thought that there are other areas which you might address which might give you a bigger improvement. When I worked for IBM on a z/OS product, we had lots of PC requests. These never really showed up as hot spots. We got improvements from better storage management (avoid getmains/freemains) data arrangement and alignment (and on a 4KB page boundary), elimination of thread interaction at the cache block level.... Colin On Sun, 14 Jan 2024 at 17:13, Binyamin Dissen <[email protected]> wrote: > On Sun, 14 Jan 2024 15:57:47 +0000 Peter Relson > <[email protected]> wrote: > > :>Binyamin wrote<snip> does that means that the CSFDLL functions do > not create a :>linkage stack entry before calling the true > routines/</snip> :>Could you share why it matters to you if there is a > linkage stack entry (whether before or after getting to the "true > routine", even if my guess is right about what you think of as the > "true routines")? > > Performance. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
