My initial purpose is actually part of implementing COBOL-compatible min-heap priority queue functions that return equal-priority nodes in FIFO insert order when popped. A timestamp or some other monotonically increasing integer tie-breaker provided with the input priority value is necessary to preserve FIFO order when pushing new items into the queue. As Paul (gil) pointed out, named counters might provide a similar function but would be far more performance-expensive compared to a simple STCK value.
Yes, I am aware that STCK breaks at the epoch in 2038 (or is it 2042? I forget now), which isn’t ALL that far away. A MetalC implementation for STCK values has been coded and works acceptably, as does of course a straight-forward assembler implementation. Extension to use STCKE instead of STCK would be trivial in either case, but of course that also doubles the space occupied by the tiebreaker value. I would much prefer an IBM-maintained solution that crosses the epoch barrier transparently. A reasonably-well-performing implementation of the C function “clock_gettime()” would probably do the trick, if it was callable from COBOL. David C. pointed out in an earlier reply that IBM XL C now has this function, if I can figure out how to invoke it from COBOL. IBM is not always very good at providing illustrative examples for inter-language cases like this. As for the actual business purpose, I’m not at liberty to discuss that. Peter From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Binyamin Dissen Sent: Monday, February 19, 2024 4:09 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Nanosecond resolution timestamps for HLL's? I don't understand how you will use this. What is the business purpose? On Sun, 18 Feb 2024 18:22:53 -0600 Peter Farley <0000031df298a9da-dmarc-requ...@listserv.ua.edu<mailto:0000031df298a9da-dmarc-requ...@listserv.ua.edu>> wrote: :>I have been reviewing all the documentation I can find to provide nano-second resolution timestamps from a calling HLL batch program. STCK and STCKE instructions of course provide this (and more) resolution, but using them from any HLL besides C/C++ requires an assembler subroutine (however simple that may be for those of us who are already comfortable in assembler). In shops where any new assembler functionality is proscribed or strongly discouraged can't or would strongly prefer not to use assembler for this functionality. :>The only HLL-callable function already provided in z/OS that I can find that provides anything near that resolution is the LE Callable Services function CEEGMT, but two calls to that service from a COBOL program in a row separated by only a few calculations and a DISPLAY to SYSOUT produce identical values. This is not good enough for high-volume processing needs. Every request for a time value needs to generate a new higher value. :>Is there any other place I am not yet looking which provides nano-second resolution like STCK/STCKE and the linux function clock_gettime() besides an assembler invocation of STCK/STCKE? z/OS Unix has not yet implemented the clock_gettime() function anyway, so that is off the table. The calling HLL here will be COBOL, so the C/C++ builtin functions "__stck" and "__stcke" are not available. Would that they were, but they are not at this time. (Maybe that calls for a new "idea" to IBM . . . ?) :>HTH for any pointers or RTFM you can provide. -- 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 lists...@listserv.ua.edu with the message: INFO IBM-MAIN
