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From: Zach Saw <zach.saw@gmail.com>
Subject: Re: App runs 8x slower on dual core machine (with test case to replicate issue)
Date: Fri, 10 Aug 2012 04:06:49 +0000 (UTC)
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Linda Walsh <cygwin <at> tlinx.org> writes:

> I can confirm the perl test case:
> 
> Using the referenced prog:
> on Linux:
> cyg-perl-thread-test.pl
> This is perl 5, version 14, subversion 2 (v5.14.2) built for 
> x86_64-linux-thread-multi
> Processing 10 tasks in 1 threads completed in 0.468952secs
> Processing 10 tasks in 4 threads completed in 0.156822secs
> cat /proc/cpuinfo/Hz|sort |uniq
> model name      : Intel(R) Xeon(R) CPU           X5660  @ 2.80GHz
> cpu MHz         : 1596.000
> 
> On Cygwin:
> This is perl 5, version 14, subversion 2 (v5.14.2) built for 
> cygwin-thread-multi-64int
> Processing 10 tasks in 1 threads completed in 1.060806secs
> Processing 10 tasks in 4 threads completed in 9.640635secs
> /Users/law> cat /proc/cpuinfo|grep Hz|sort -r |uniq
> model name      : Intel(R) Xeon(R) CPU           X5680  @ 3.33GHz
> cpu MHz         : 3325

Just out of curiousity are you running XP-32bit?
If you are, could you try running the multithreaded test with CPU 
affinity set to 1 (single core)?
You should see it take just a little more time to complete vs the
single threaded one.


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