X-Recipient:	archive-cygwin AT delorie DOT com
X-Spam-Check-By:	sourceware.org
Message-ID:	<4831DA8F.6070006@t-online.de>
Date:	Mon, 19 May 2008 21:52:47 +0200
From:	Christian Franke <Christian DOT Franke AT t-online DOT de>
User-Agent:	Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.11) Gecko/20071128 SeaMonkey/1.1.7
MIME-Version:	1.0
To:	cygwin AT cygwin DOT com
Subject:	Re: fork performance
References:	<48310648 DOT 90406 AT gmx DOT de> <20080519081124 DOT GD731 AT calimero DOT vinschen DOT de>
In-Reply-To:	<20080519081124.GD731@calimero.vinschen.de>
X-ID:	TWM4qsZCgh3tl0GliNg1k9o3YDDmxlvIdbKQXbQBc3CLYD+xRTKkud2+orso+RSg8U
X-TOI-MSGID:	5964ecb5-23a9-4dbc-890c-9b84f1fac85b
X-IsSubscribed:	yes
Mailing-List:	contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id:	<cygwin.cygwin.com>
List-Subscribe:	<mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive:	<http://sourceware.org/ml/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender:	cygwin-owner AT cygwin DOT com
Mail-Followup-To:	cygwin AT cygwin DOT com
Delivered-To:	mailing list cygwin AT cygwin DOT com

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


--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/

- Raw text -