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Date: Fri, 14 Dec 2007 12:41:10 +0800
From: Erich Dollansky <oceanare@pacific.net.sg>
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To: Shantanu Ghosh <shantanu_ghosh@yahoo.com>
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Cc: freebsd-performance@freebsd.org
Subject: Re: freebsd vs linux: performance problem
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Hi,

Shantanu Ghosh wrote:
> --- Erich Dollansky <oceanare@pacific.net.sg> wrote:
> 
>> Shantanu Ghosh wrote:
>>> --- Erich Dollansky <oceanare@pacific.net.sg> wrote:
>>>
>> I have had once the problem of a task moving from CPU to CPU and s 
>> performing badly on FreeBSD.
>>
>> I am not informed how this is handled currently.
> 
> This could be something I am facing. I noticed that when I run vmstat
> while running this code, on linux, there's hardly any perceptible
> difference in the number of context switches, but on freebsd, the
> number of context switches in the system seems to go up a bit. However,
> this is not very reliable.
> 
> Do you know how I can check this migration?

I forgot how I checked it.
> 
> While I have not tried it on this machine, on a single cpu machine, the
> non-SMP build of freebsd seems to perform as well as linux for this
> kind of test.

Ok, this could then be a hint that the task is simply migrating.
> 
> Thanks a lot for your help.

No not praise the day before night falls.

Erich