[Bug target/109812] GraphicsMagick resize is a lot slower in GCC 13.1 vs Clang 16 on Intel Raptor Lake

[liuhongt at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109812

--- Comment #23 from Hongtao Liu <liuhongt at gcc dot gnu.org> ---
(In reply to edison from comment #22)
> for 607.cactuBSSN_s,if use preENV_GOMP_CPU_AFFINITY = 0-23 in CPU2017 .cfg,
> all  p-core(i9-13900k) usage will down to 15%(the e-core almost 100%), if
> comment out it all p-core usage will up to 60%.
> 
> 607.cactuBSSN_s on i9-13900K
> gcc 14.1
> 
> preENV_GOMP_CPU_AFFINITY = 0-23：   60.1 (-41.7 % slower)
> # preENV_GOMP_CPU_AFFINITY = 0-23： 103
> 
> but for AMD Zen4(+) that maybe another story so far(AMD Zen4 need
> preENV_GOMP_CPU_AFFINITY to make the threads run on high performance core
> first).

Because E-core run slower than P-core, if you bind the thread to each core, it
prevents threads from migrating from the E-core to the P-core.