[PATCH] libstdc++: Introduce scale factor in 30_threads/future/members/poll.cc [PR98678]

[Jonathan Wakely]

On Mon, 10 Jun 2024 at 12:54, Rainer Orth <ro@cebitec.uni-bielefeld.de> wrote:
>
> 30_threads/future/members/poll.cc consistently FAILs on Solaris/x86
> (both 32 and 64-bit):
>
> FAIL: 30_threads/future/members/poll.cc  -std=gnu++17 execution test

I see this one failing under x86_64-linux under high load. So I think
we might simply want a better test.


>
> /vol/gcc/src/hg/master/local/libstdc++-v3/testsuite/30_threads/future/members/poll.cc:95: int main(): Assertion 'wait_until_sys_min < (ready * 100)' failed.
> wait_for(0s): 11892ns for 200 calls, avg 59.46ns per call
> wait_until(system_clock minimum): 1304458ns for 200 calls, avg 6522.29ns per call
> wait_until(steady_clock minimum): 1403221ns for 200 calls, avg 7016.1ns per call
> wait_until(system_clock epoch): 3343806ns for 200 calls, avg 16719ns per call
> wait_until(steady_clock epoch: 2959581ns for 200 calls, avg 14797.9ns per call
> wait_for when ready: 10969ns for 200 calls, avg 54.845ns per call
>
> As reported in the PR, across a considerable range of CPUs the test
> doesn't complete in the expected time.  Therefore, this patch introduces
> a Solaris/x86 specific scale factor to allow for that.
>
> There's no such issue on Solaris/SPARC, though.
>
> Tested on i386-pc-solaris2.11 and sparc-sun-solaris2.11.
>
> Ok for trunk?
>
>         Rainer
>
> --
> -----------------------------------------------------------------------------
> Rainer Orth, Center for Biotechnology, Bielefeld University
>
>
> 2024-06-04  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
>
>         libstdc++-v3:
>         PR libstdc++/98678
>         * testsuite/30_threads/future/members/poll.cc (main): Introduce
>         scale factor.
>