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

From: Karen Shaeffer <[email-masked]>
Date: Thu, 24 Oct 2002 02:37:51 -0700

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
 [email-masked]  http://www.neuralscape.com