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

To: "David S. Miller" <davem@xxxxxxxxxxxxx>
Subject: Re: [RESEND] tuning linux for high network performance?
From: Karen Shaeffer <shaeffer@xxxxxxxxxxxxxxx>
Date: Thu, 24 Oct 2002 02:37:51 -0700
Cc: netdev@xxxxxxxxxxx
In-reply-to: <1035432669.9628.1.camel@xxxxxxxxxxxxx>; from davem@xxxxxxxxxxxxx on Wed, Oct 23, 2002 at 09:11:09PM -0700
References: <200210231218.18733.roy@xxxxxxxxxxxxx> <20021023130101.GA646@xxxxxxxxxxxxxxx> <1035379308.5950.3.camel@xxxxxxxxxxxxx> <200210231542.48673.roy@xxxxxxxxxxxxx> <1035432669.9628.1.camel@xxxxxxxxxxxxx>
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On Wed, Oct 23, 2002 at 09:11:09PM -0700, David S. Miller wrote:
> On Wed, 2002-10-23 at 06:42, Roy Sigurd Karlsbakk wrote:
> > As far as I've understood, sendfile() won't do much good with large files. 
> > Is 
> > this right?
> 
> There is always a benefit to using sendfile(), when you use
> sendfile() the cpu doesn't touch one byte of the data if
> the network card support TX checksumming.  The disk DMAs
> to ram, then the net card DMAs from ram.  Simple as that.

Referring to:

$ rpm -qf /usr/include/sys/sendfile.h
glibc-devel-2.2.5-40

quoting "sendfile.h"

#ifdef __USE_FILE_OFFSET64
# error "<sys/sendfile.h> cannot be used with _FILE_OFFSET_BITS=64"
#endif

So, how does one use sendfile() for large files that are greater than 2
GBytes? Am I missing something?

Thanks,
Karen
-- 
 Karen Shaeffer
 Neuralscape; Santa Cruz, Ca. 95060
 shaeffer@xxxxxxxxxxxxxxx  http://www.neuralscape.com


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