Thu Aug 12 12:05:35 CEST 2010

Condition variable vs. semaphore

In PDP I used condition variables to signal queue writes.  This seems
to be incorrect.  Semaphores are actually a lot better for managing
work queues.

First, they are simpler to use, but second they also can ensure that
no events are missed.  I.e. during the handling of a changed
condition, the condition might change multiple times, which is missed
by the handling thread.