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From: bert hubert <ahu@ds9a.nl>
To: P?l Halvorsen <paalh@ifi.uio.no>
Cc: linux-kernel@vger.kernel.org
Subject: Re: sendfile
Date: Wed, 30 Apr 2003 21:28:09 +0200	[thread overview]
Message-ID: <20030430192809.GA8961@outpost.ds9a.nl> (raw)
In-Reply-To: <Pine.SOL.4.51.0304302102300.12387@ellifu.ifi.uio.no>

On Wed, Apr 30, 2003 at 09:12:17PM +0200, P?l Halvorsen wrote:

> It could be useful for applications like streaming video where other
> protocols on top provide additional functionality or in a multicast
> session where TCP migth not be appropriate.

sendfile on UDP would try to send gigabits per second over ppp0...

> But should not the 2.4.X kernels have support for chained sk_buffs (like
> the BSD mbufs) meaning that support for scatter-gatter I/O from the NIC
> should be unneccessary to support zero-copy (i.e., NO in-memory data
> copy operations)?

No clue what you mean over here. Zero copy means different things to
different people. Sendfile eliminates the 'read(to buffer);write(buffer to
network);' copy. 

Some network drivers again may eliminate the 'copy_with_checksum()' step,
allowing minus-one-copy, in zerocopy reference frame.

Regards,

bert


-- 
http://www.PowerDNS.com      Open source, database driven DNS Software 
http://lartc.org           Linux Advanced Routing & Traffic Control HOWTO

  reply	other threads:[~2003-04-30 19:15 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-04-30 14:28 sendfile Pål Halvorsen
2003-04-30 16:51 ` sendfile bert hubert
2003-04-30 19:12   ` sendfile Pål Halvorsen
2003-04-30 19:28     ` bert hubert [this message]
2003-04-30 21:57       ` sendfile Pål Halvorsen
2003-04-30 22:18         ` sendfile Mark Mielke
2003-04-30 22:34           ` sendfile Pål Halvorsen
2003-05-01  4:28             ` sendfile Mark Mielke
2003-05-01 15:25               ` sendfile Joseph Malicki
2003-05-01 21:17               ` sendfile Pål Halvorsen
2003-05-01 22:31                 ` sendfile Chris Friesen
2003-05-01 23:32                   ` sendfile Ketil Froyn
2003-05-02  9:02                     ` sendfile Bernd Eckenfels
2003-05-02  2:41                   ` sendfile Mark Mielke
2003-05-02  4:19                     ` sendfile Chris Friesen
2003-05-02 21:06                       ` sendfile Mark Mielke
2003-05-03  0:42                         ` sendfile Miquel van Smoorenburg
2003-05-03 15:04                           ` sendfile Mark Mielke
2003-05-03 12:52                         ` sendfile Pål Halvorsen
2003-05-03 21:01                         ` sendfile Pål Halvorsen
2003-05-04  0:53                           ` sendfile Miquel van Smoorenburg
  -- strict thread matches above, loose matches on Subject: below --
2001-05-24  8:44 sendfile Pål Halvorsen

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