On 07/15/2011 02:37 AM, Jakub Jelinek wrote: > Any comments? Can anyone see meassurable differences on some benchmark? > > 2011-07-15 Jakub Jelinek <ja...@redhat.com> > > * config/linux/wait.h (do_spin): New inline, largely copied > from do_wait, just don't do futex_wait here, instead return true if > it should be done. > (do_wait): Implement using do_spin. > * config/linux/mutex.h (gomp_mutex_lock_slow): Add an int argument > to prototype. > (gomp_mutex_lock): Use __sync_val_compare_and_swap instead of > __sync_bool_compare_and_swap, pass the oldval to > gomp_mutex_lock_slow. > * config/linux/mutex.c (gomp_mutex_lock_slow): Add oldval argument. > If all mutex contenders are just spinning and not sleeping, don't > change state to 2 unnecessarily. Optimize the loop when state has > already become 2 to use just one atomic operation per loop instead > of two. > * config/linux/ia64/mutex.h (gomp_mutex_lock_slow): Add an int argument > to prototype. > (gomp_mutex_lock): Use __sync_val_compare_and_swap instead of > __sync_bool_compare_and_swap, pass the oldval to > gomp_mutex_lock_slow.
I think that even if the only measurable difference is a reduction in the number of syscalls, that's still an improvement. The patch is ok. r~
