Re: [PATCH] libgomp: Fix default value of GOMP_SPINCOUNT [PR 109062]

[Hongyu Wang <wwwhhhyyy333@gmail.com>]

Hongyu Wang <wwwhhhyyy333@gmail.com> 于2023年3月8日周三 16:07写道：
>
> > I think the right spot to fix this would be instead in initialize_icvs,
> > change the
> >   icvs->wait_policy = 0;
> > in there to
> >   icvs->wait_policy = -1;
> > That way it will be the default for all the devices, not just the
> > initial one.
>
> It doesn't work, for the code that determines value of wait_policy:
>
> 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;
>
> gomp_get_icv_flag (none->flags, GOMP_ICV_WAIT_POLICY) returns true only when
> OMP_WAIT_POLICY is explicitly set, so the initial icvs->wait_policy
> could not affect the global wait_policy that used to set
> GOMP_SPINCOUNT.

Also the global variable wait_policy here is only used for setting
spin_count related values that do not
belong to any ICV, so there is no need to set icvs->wait_policy since
for OMP_WAIT_POLICY_(DEV|ALL)
itself only has value 0 for passive and value 1 for active.