Hi, we have encountered random hangs and crashes in cygwin (see output of cygcheck attached to this message) on a dual-processor server running Windows Server 2003. IMHO, the so-called "hyperthreading problems" reported recently on this mailing list just have nothing to do with hyperthreading, but are more generally related to multi-processor issues. I used the following test (found on this mailing list archive, posted 6 Apr 2004 by Chuck McDevitt):
<QUOTE> #! /bin/ksh mypath=$(pwd) while [[ ! -z $mypath ]] do mypath=$(pwd) if [[ -z $mypath ]] then echo "Test Failed......Path is empty" fi done in one shell, while running a large make in another, it will fail in a variety of ways. Under pdksh, it sometimes exits the test because "mypath" is empty, or it core dumps, or hangs, or gives error messages. Under bash, it hangs, crashes, or gives error messages (haven't seen it exit the loop, but I didn't try long with bash). By "hang", I mean the shell stops using CPU time, and become non-responsive, and can only be stopped by killing the process. The problem does not occur if hyperthreading is turned off. </QUOTE> When booting the server in single CPU (/ONECPU in boot.ini) the problem does not appear. More interesting, if I lock my bash session on a particular CPU by using SetProcessAffinityMask, so that all child processes created by this shell are locked on one CPU, the problem does not appear. It seems that the bug has something to do with a same Cygwin process being swapped from one CPU to another when running a piece of code that is not locked properly (i.e. missing EnterCriticalSection or something like that). Regards, Stephane
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