cheap special-case optimization for normal mutexes
authorRich Felker <dalias@aerifal.cx>
Wed, 30 Mar 2011 12:58:25 +0000 (08:58 -0400)
committerRich Felker <dalias@aerifal.cx>
Wed, 30 Mar 2011 12:58:25 +0000 (08:58 -0400)
commit124b4ebc8a293e616cc0a7eaba3587c9b7ff13ec
tree80c2bdc3f961b6acb7344d5b8eaf725d219458d0
parent680630011d38eb9f96f92b2f080cc60f38f6df21
cheap special-case optimization for normal mutexes

cycle-level benchmark on atom cpu showed typical pthread_mutex_lock
call dropping from ~120 cycles to ~90 cycles with this change. benefit
may vary with compiler options and version, but this optimization is
very cheap to make and should always help some.
src/thread/pthread_mutex_lock.c