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Date: Thu, 09 Aug 2012 20:52:35 -0700
From: Linda Walsh <cygwin AT tlinx DOT org>
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Subject: Re: App runs 8x slower on dual core machine (with test case to replicate issue)
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Zach Saw wrote:
> Corinna Vinschen <corinna-cygwin <at> cygwin.com> writes: 
>> Thanks for the testcase, but... would you mind to change it to take the
>> boost lib out of the picture, by using just plain pthread functions, if
>> possible in plain C?
> 
> Apparently someone else has already encountered similar problems in 
> cygwin perl 
> (http://www.nntp.perl.org/group/perl.perl5.porters/2011/07/msg174491.html)
--------------
--
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

---
Note -- neither of my cpu's have "HT" enabled.. So in both
cases 'threads' must use separate processes...



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