Subj : Re: Hyper Threading / Multi-Threaded Queue / Application Freezes
To   : comp.programming.threads
From : dayton
Date : Wed Apr 13 2005 05:57 pm

>>  have an MFC application which contains a queue which is accessed by
>> multiple threads. [...]
>> My problem is this program has run great on 100's of machines for well
>> over 12months, however recently has been tested on a Hyper-Threaded XP
>> SP2 machine - and for some reasons the application locks up
>> periodically.  By "locks up", I mean the application frame freezes (not
>> responding) for up to 10-20secs at a time and then returns to normal
>> again.

Of course it could just be Windows.  We've had uniform trouble enabling 
hyperthreading in the BIOS in the machines here at work.  Our Windows XP 
and Windows 2000 Server machines crash in 24-48 hours with a Blue Screen 
of Death, or just occasionally hang.  These crashes occur under no load, 
that is, no applications, just Windows running.

MFC critical sections, though, indicate an old fashioned programmer 
induced deadlock.  Critical sections occur entirely in your application 
space.  Look up the edge locking design pattern and apply it with 
enthusiasm.  For that matter, look at the interlocked compare and swap 
functions.  You probably don't even need critical sections.  There are 
some papers you can find on the Web on implementing non-blocking 
concurrent queues.

Make sure your application isn't doing anything fancy like using MFC 
extension DLLs, and COM.  MFC has an infamous deadlock in load/unload 
library code.

.