Slow fork issue - Win x64

[Paul-Kenji Cahier <pkc at F1-Photo dot com>]

Hello,

I have been noticing extreme slowdowns in vista/2k8 64 with latest cygwin 1.5.
Fresh installation, no antivirus.

The command used to test speed is:
while (true); do date; done | uniq -c

On windows 2008 64bit:
     11 Wed Sep 17 20:35:22 RDT 2008
     11 Wed Sep 17 20:35:23 RDT 2008
     12 Wed Sep 17 20:35:24 RDT 2008
     11 Wed Sep 17 20:35:25 RDT 2008
     12 Wed Sep 17 20:35:26 RDT 2008
     11 Wed Sep 17 20:35:27 RDT 2008
     12 Wed Sep 17 20:35:28 RDT 2008
     11 Wed Sep 17 20:35:29 RDT 2008
     11 Wed Sep 17 20:35:30 RDT 2008

On windows XP SP3 32bit:
     51 Wed Sep 17 20:35:42     2008
     50 Wed Sep 17 20:35:43     2008
     50 Wed Sep 17 20:35:44     2008
     51 Wed Sep 17 20:35:45     2008
     50 Wed Sep 17 20:35:46     2008
     51 Wed Sep 17 20:35:47     2008
     48 Wed Sep 17 20:35:48     2008
     50 Wed Sep 17 20:35:49     2008
     50 Wed Sep 17 20:35:50     2008

I of course wont compare to linux since the situation is quite different(and cygwin's fork
has a lot more work to do)

At first I thought it was a syswow64(windows on windows 64, the windows 32 subsystem of windows 64bit)
that was causing the issue since cygwin is 32 bit.

But then I ran the following test:
Running 200 times the 32bit cmd.exe /C exit from cygwin and from a normal 32bit windows cmd.
To my great surprise cygwin took 14seconds, while cmd took 2.5seconds.
The only difference I can see between the two is that cygwin's fork does more work...
But should it really be such a big difference?

Thanks for any hints,  

-- 
Best regards,
 Paul-Kenji                          mailto:pkc@F1-Photo.com


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