DualCores and Current Cygwin problems

Linda Walsh cygwin@tlinx.org
Sat May 12 21:38:00 GMT 2007

Hi, I don't claim to know what is going on, but I'm
using a dual-core system and haven't noticed the problems you are having,
but my processors are Intel Dual Core.  That shouldn't make a difference
I wouldn't think.

Joseph Kowalski wrote:
> 1) Windows XP, fully updated;   2) Visual Studio .NET Professional (2003)
> 3) Microsoft Platform SDK (2004 - *not* R2)
> 4) Microsoft DirectX SDK (Summer 2004);   5) Sun Java 6 SDK (1.6.0_01)
> 6) Cygwin (current).  That's it.  No additional software components.  None.
	What do you mean by "components"?  Do you mean if you go into
the "Add/Remove Programs", the only items I would see would be the MS SDK,
XP "Patches", DirectX SDK, and Sun Java?  If you tell it to hide "updates",
I'd guess you only have 3 items on your Software list?  the MS-Platform SDK,
the DirectX SDK and the Sun Java SDK?  (Cygwin wouldn't be listed).

	That's a pretty short list, but I assume it is a test machine
that's off the main net and is only for testing?

> With this configuration, I get random "can not fork: Resource 
> temporarily unavailable" errors ... [and]  "dup_proc_pipe" failures, which
> are fairly random, but tend to be understandably associated with long 
> pipes in the build process.
> If I add /ONECPU to boot.ini, neatly turning my DualCore system into a 
> single core system, the failures all magically disappear.
	Using "Process Explorer" from sysinternals.com (now owned by MS), one can
set "affinities" for processes that should limit your processes to 1 cpu.  Children
from a processor-limited process inherit the "affinities".

	I'm wondering -- just as a data point, if you tried building on a
dual-core, but setting all of your cygwin processes to run on one core?

> This would tend to indicate that there is a multi-threading issue either 
> in cygwin or in the underlying Windows XP operating environment.
	Sounds plausible -- all of your drivers are one's included in XP?
Maybe, perversely, you could try drivers from your hardware manufacturers and
see if they work better?  On a previous machine, I installed drivers for my
motherboard from Intel site.  Another difference (that shouldn't make a difference)
is the BIOS code -- I have run into BIOS code, *many* years ago, that wasn't
reentrant --- made it a pain to work with.   But with multiple cpu's, that's a
more challenging layer of re-entrancy than single-cpu multi-tasking/threading.

	But maybe making sure you have latest drivers from manufacturers
even though they may not be coming with your standard WinXP install would


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