To: cygwin@cygwin.com
From: Andy Nicholas <andy.nicholas.mail@gmail.com>
Subject: Cygwin speed difference on multiple cores -vs- single-core?
Date: Sat, 14 Aug 2010 00:37:45 +0000 (UTC)
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Hi Folks,

When using cygwin, I've noticed that there seems to be a large speed 
difference when I boot my windows 7 (32-bit) machine in single-core mode 
versus the regular number of cores (4, Core i7-930).

I've read through the FAQ and didn't notice anything about this issue.

Normally, I would expect nearly no speed difference based on the Windows 
environment... but after some extensive timing tests it seems like the single-
core machine is usually at least 2x faster than using the same machine setup 
in multi-core mode. I limit the number of cores using MSCONFIG, advanced boot 
options.

We have some simple script and more complex scripts which show this behavior. 
The simple scripts do straightforward things like "rm -rf" over some directory 
trees. Even the simple scripts run slowly when the PC is booted with multiple 
cores.

Is this known behavior? Is there some way to work around it so I can boot my 
PC, use all the cores with other apps, and continue run cygwin 2x faster?

Thanks much,

andy


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