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Date: Mon, 19 May 2008 21:52:47 +0200
From: Christian Franke <Christian DOT Franke AT t-online DOT de>
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To: cygwin AT cygwin DOT com
Subject: Re: fork performance
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Corinna Vinschen wrote:
> On May 19 06:47, Reinhard Nissl wrote:
>   
>> Hi,
>>
>> running the following command sequence in bash yields little numbers 
>> compared to a real unix system:
>>
>> 	while true ; do date ; done | uniq -c
>>
>>       15 Thu May 15 10:40:22     2008
>>       16 Thu May 15 10:40:23     2008
>>       17 Thu May 15 10:40:24     2008
>>       17 Thu May 15 10:40:25     2008
>>       17 Thu May 15 10:40:26     2008
>>       16 Thu May 15 10:40:27     2008
>>       17 Thu May 15 10:40:28     2008
>>       16 Thu May 15 10:40:29     2008
>>
>> Is there a chance to speedup performance?
>>     
>
> Cygwin's fork() implementation is *not* deliberately slow.  Take a look
> into the sources, file fork.cc, and see what it has to do.  Having said
> that, of course http://cygwin.com/acronyms/#PTC
>
>
>   

BTW: Even Linux fork() is only fast if it has access to real memory 
management hardware. In a VM, considerable slowdown occurs.

Average "date per second" results from above command on same machine:

Linux native:     780
Linux VMware:     255
Linux VirtualBox: 145
Linux VirtualPC:   60
Cygwin:            56 (AV off, Kerio Fw off)
Cygwin:            48 (AV on,  Kerio Fw off)
Cygwin:            25 (AV off, Kerio Fw on)

Christian


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