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From: Roy Sigurd Karlsbakk <roy@karlsbakk.net>
Organization: ProntoTV AS
To: Nivedita Singhvi <niv@us.ibm.com>, bert hubert <ahu@ds9a.nl>
Subject: O_DIRECT sockets? (was [RESEND] tuning linux for high network performance?)
Date: Wed, 23 Oct 2002 17:26:21 +0200
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On Wednesday 23 October 2002 16:59, Nivedita Singhvi wrote:
> bert hubert wrote:
> > > ...adding the whole profile output - sorted by the first column this
> > > time...
> > >
> > > 905182 total                                      0.4741
> > > 121426 csum_partial_copy_generic                474.3203
> > >  93633 default_idle                             1800.6346
> > >  74665 do_wp_page                               111.1086
> >
> > Perhaps the 'copy' also entails grabbing the page from disk, leading to
> > inflated csum_partial_copy_generic stats?
>
> I think this is strictly a copy from user space->kernel and vice versa.
> This shouldnt include the disk access etc.

hm

I'm doing O_DIRECT read (from disk), so it needs to be user -> kernel, then.

any chance of using O_DIRECT to the socket?

-- 
Roy Sigurd Karlsbakk, Datavaktmester
ProntoTV AS - http://www.pronto.tv/
Tel: +47 9801 3356

Computers are like air conditioners.
They stop working when you open Windows.

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