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Re: [RESEND] tuning linux for high network performance?

To: Roy Sigurd Karlsbakk <roy@xxxxxxxxxxxxx>
Subject: Re: [RESEND] tuning linux for high network performance?
From: bert hubert <ahu@xxxxxxx>
Date: Wed, 23 Oct 2002 15:01:01 +0200
Cc: netdev@xxxxxxxxxxx, Kernel mailing list <linux-kernel@xxxxxxxxxxxxxxx>
In-reply-to: <200210231306.18422.roy@xxxxxxxxxxxxx>
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On Wed, Oct 23, 2002 at 01:06:18PM +0200, Roy Sigurd Karlsbakk wrote:
> > I've got this video server serving video for VoD. problem is the P4 1.8
> > seems to be maxed out by a few system calls. The below output is for ~50
> > clients streaming at ~4.5Mbps. if trying to increase this to ~70, the CPU
> > maxes out.

'50 clients *each* streaming at ~4.4MBps', better make that clear, otherwise
something is *very* broken. Also mention that you have an e1000 card which
does not do outgoing checksumming.

You'd think that a kernel would be able to do 250megabits of TCP checksums
though.

> ...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?

Where are you serving from?

Regards,

bert

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