[Bug tree-optimization/82604] [8 Regression] SPEC CPU2006 410.bwaves ~50% performance regression with trunk@253679 when ftree-parallelize-loops is used

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82604

--- Comment #22 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
libgomp has many ways to tweak the wait behavior, look for OMP_WAIT_POLICY and
GOMP_SPINCOUNT environment variables to tweak the spinning vs. futex waiting.
Is the work scheduled for each thread roughly the same or are there threads
that do more work than others?  There is also
--param parloops-schedule={static,dynamic,guided,auto,runtime} with which you
can choose different kinds of OpenMP scheduling, with runtime even using env
vars.