Subj : Re: Either I'm stupid, or NPTL 0.29 on RH9 is broken!
To   : comp.programming.threads
From : Greg Law
Date : Tue Jan 25 2005 09:38 am

Nope -- adding the sched_yield makes no difference.

Also, given that I'm running on an SMP machine,  I would (perhaps
naively?) have expected the scheduler to allow the other CPU in when
the mutex was released.  (The second CPU is shown as pretty much
completely idle).

Also, changing the signal to a broadcast "fixes" it -- evidence that
the pthread_cond_signal is going astray.

I do take the point that strictly speaking this can be seen as
conformant behavior -- POSIX gives no guarantees about "fairness" of
scheduling.  However, it strikes me as not the behavior would normally
expect!

.