[PATCH 02/10] locking/qspinlock: Remove unbounded cmpxchg loop from locking slowpath

[Peter Zijlstra]

On Fri, Apr 06, 2018 at 04:50:19PM -0400, Waiman Long wrote:
>   # of threads  4.16 kernel     patched 4.16 kernel
>   ------------  -----------     -------------------
>         1       7,417 kop/s         7,408 kop/s
>         2       5,755 kop/s         4,486 kop/s
>         3       4,214 kop/s         4,169 kop/s
>         4       4,396 kop/s         4,383 kop/s
>        

Interesting, I didn't see that dip in my userspace tests.. I'll have to
try again.