bf29ee2a49
pthread_cond_signal does not need the mutex to be held to signal. This results in the thread waking up trying to grab the lock, failing, the signaling thread to wake up, release the lock, immediately get preempted for the signaled thread which can now proceed. Release the mutex before signaling to avoid the ping-pong scheduling issue, which shaves another 10us off of this Change-Id: Ie6bccca031ba6528f357eae8352b74626a6318c7