On Thu, 2006-08-24 at 08:56 +0100, Simon Marlow wrote:
Hi Folks,
Roman Leshchinskiy and I looked into the 6.4.3 crashes on Sparc/Solaris yesterday. I think we may have found the problem, and it seems likely that this is the same problem affecting 6.4.3 on MacOS X. The threaded RTS is assuming in a couple of places that pthread_cond_wait() doesn't spuriously wake up, which is apparently the case on Linux but not true in general.
I don't believe it is the case on Linux either. I had the same problem: on Linux it appears to work .. but Posix allows spurious wakeups, our OSX/Solaris/Windows code failed. This isn't just for cond_wait: most system calls can return spuriously if an OS signal goes off. Somewhere I read a good article explaining why this is necessary for good performance. A signal to a condition variable should be regarded as a hint to recheck the condition. -- John Skaller <skaller at users dot sf dot net> Felix, successor to C++: http://felix.sf.net