Date: Wed, 23 Oct 2002 19:01:02 +0200
From: bert hubert <ahu@ds9a.nl>
To: Roy Sigurd Karlsbakk <roy@karlsbakk.net>
Cc: "David S. Miller" <davem@rth.ninka.net>, netdev@oss.sgi.com,
   Kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: [RESEND] tuning linux for high network performance?
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On Wed, Oct 23, 2002 at 03:42:48PM +0200, Roy Sigurd Karlsbakk wrote:
> > The e1000 can very well do hardware checksumming on transmit.
> >
> > The missing piece of the puzzle is that his application is not
> > using sendfile(), without which no transmit checksum offload
> > can take place.
> 
> As far as I've understood, sendfile() won't do much good with large files. Is 
> this right?

I still refuse to believe that a 1.8GHz Pentium4 can only checksum
250megabits/second. MD Raid5 does better and they probably don't use a
checksum as braindead as that used by TCP.

If the checksumming is not the problem, the copying is, which would be a
weakness of your hardware. The function profiled does both the copying and
the checksumming.

But 250megabits/second also seems low.

Dave? 

Regards,

bert

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