Problems with multi-threaded application and Dual Xeon MP system

[John Haxby <jch scalix com>]

Hello All,

   We're having problems here with a multi-threaded application running 
on a dual Xeon MP machine --pthread_mutex_lock() is take a very long 
time to acquire the lock, anything up to about 30s sometimes.   With 
only 50 threads competing for this critical section this seems a tad 
unreasonable.   Especially when the same application running the same 
load on hardware that is only substantially different in the CPU type 
(plain Xeon instead of Xeon MP) doesn't show any evidence of any thread 
getting stuck in pthread_mutex_lock().

I do vaguely recall someone mentioning problems along these lines on one 
of the lists, but I'm blowed if I can find it again.   Does this problem 
ring any bells with anyone?

jch