[Bug libstdc++/98678] 30_threads/future/members/poll.cc execution test FAILs

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98678

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-01-14
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The relevant part of the std::future code on the gcc-10 branch is very
different, so the timings are different on the branch too.

This test is a bit tricky. The whole point is to check that performance of one
operation is acceptable compared to a baseline. But the definition of
"acceptable" and the relative difference between the speed of the different
operations varies with arch. We could just increase the tolerances, but then we
allow worse performance on the targets that don't need it. Maybe we want to
change the 30 and 100 magic numbers to depend on the target.