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* [Bug libgomp/109062] New: [13 regression] Default value of GOMP_SPINCOUNT changes since r13-2545 @ 2023-03-08 3:23 wwwhhhyyy333 at gmail dot com 2023-03-08 7:51 ` [Bug libgomp/109062] " rguenth at gcc dot gnu.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: wwwhhhyyy333 at gmail dot com @ 2023-03-08 3:23 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109062 Bug ID: 109062 Summary: [13 regression] Default value of GOMP_SPINCOUNT changes since r13-2545 Product: gcc Version: 13.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libgomp Assignee: unassigned at gcc dot gnu.org Reporter: wwwhhhyyy333 at gmail dot com CC: jakub at gcc dot gnu.org Target Milestone: --- Recently we found several big regressions on Phoronix OpenMP benchmark on GCC13. The regressions is caused by r13-2545-g9f2fca56593a2b The issue is, the default value of GOMP_SPINCOUNT is now 0, instead of 300000 before this patch, which caused all Openmp program behaves like OMP_WAIT_POLICY=passive. As the comments in libgomp/env.c says: /* Using a rough estimation of 100000 spins per msec, use 5 min blocking for OMP_WAIT_POLICY=active, 3 msec blocking when OMP_WAIT_POLICY is not specificed and 0 when OMP_WAIT_POLICY=passive. Depending on the CPU speed, this can be e.g. 5 times longer or 5 times shorter. */ The current code for wait_policy is if (none != NULL && gomp_get_icv_flag (none->flags, GOMP_ICV_WAIT_POLICY)) wait_policy = none->icvs.wait_policy; else if (all != NULL && gomp_get_icv_flag (all->flags, GOMP_ICV_WAIT_POLICY)) wait_policy = all->icvs.wait_policy; If OMP_WAIT_POLICY not specified, non of the branch will be entered since gomp_get_icv_flag will return 0 by default, then wait_policy remains its value as uninitialized. While prior to this patch wait_policy will be set to -1 (not specified) by parse_wait_policy (). ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug libgomp/109062] [13 regression] Default value of GOMP_SPINCOUNT changes since r13-2545 2023-03-08 3:23 [Bug libgomp/109062] New: [13 regression] Default value of GOMP_SPINCOUNT changes since r13-2545 wwwhhhyyy333 at gmail dot com @ 2023-03-08 7:51 ` rguenth at gcc dot gnu.org 2023-03-09 1:01 ` cvs-commit at gcc dot gnu.org 2023-03-09 1:07 ` wwwhhhyyy333 at gmail dot com 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2023-03-08 7:51 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109062 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |13.0 Keywords| |openmp ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug libgomp/109062] [13 regression] Default value of GOMP_SPINCOUNT changes since r13-2545 2023-03-08 3:23 [Bug libgomp/109062] New: [13 regression] Default value of GOMP_SPINCOUNT changes since r13-2545 wwwhhhyyy333 at gmail dot com 2023-03-08 7:51 ` [Bug libgomp/109062] " rguenth at gcc dot gnu.org @ 2023-03-09 1:01 ` cvs-commit at gcc dot gnu.org 2023-03-09 1:07 ` wwwhhhyyy333 at gmail dot com 2 siblings, 0 replies; 4+ messages in thread From: cvs-commit at gcc dot gnu.org @ 2023-03-09 1:01 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109062 --- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Hongyu Wang <hongyuw@gcc.gnu.org>: https://gcc.gnu.org/g:288bc7b5d17511d1791899e4b2e3bf3489eb06dd commit r13-6548-g288bc7b5d17511d1791899e4b2e3bf3489eb06dd Author: Hongyu Wang <hongyu.wang@intel.com> Date: Wed Mar 8 11:29:46 2023 +0800 libgomp: Fix default value of GOMP_SPINCOUNT [PR 109062] When OMP_WAIT_POLICY is not specified, current implementation will cause icv flag GOMP_ICV_WAIT_POLICY unset, so global variable wait_policy will remain its uninitialized value. Initialize it to -1 to make GOMP_SPINCOUNT behavior consistent with its description. libgomp/ChangeLog: PR libgomp/109062 * env.c (wait_policy): Initialize to -1. (initialize_icvs): Initialize icvs->wait_policy to -1. * testsuite/libgomp.c-c++-common/pr109062.c: New test. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug libgomp/109062] [13 regression] Default value of GOMP_SPINCOUNT changes since r13-2545 2023-03-08 3:23 [Bug libgomp/109062] New: [13 regression] Default value of GOMP_SPINCOUNT changes since r13-2545 wwwhhhyyy333 at gmail dot com 2023-03-08 7:51 ` [Bug libgomp/109062] " rguenth at gcc dot gnu.org 2023-03-09 1:01 ` cvs-commit at gcc dot gnu.org @ 2023-03-09 1:07 ` wwwhhhyyy333 at gmail dot com 2 siblings, 0 replies; 4+ messages in thread From: wwwhhhyyy333 at gmail dot com @ 2023-03-09 1:07 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109062 Hongyu Wang <wwwhhhyyy333 at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |FIXED --- Comment #2 from Hongyu Wang <wwwhhhyyy333 at gmail dot com> --- Fixed on trunk so far. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-03-09 1:07 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2023-03-08 3:23 [Bug libgomp/109062] New: [13 regression] Default value of GOMP_SPINCOUNT changes since r13-2545 wwwhhhyyy333 at gmail dot com 2023-03-08 7:51 ` [Bug libgomp/109062] " rguenth at gcc dot gnu.org 2023-03-09 1:01 ` cvs-commit at gcc dot gnu.org 2023-03-09 1:07 ` wwwhhhyyy333 at gmail dot com
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