From: Roland Dreier <rdreier@cisco.com>
To: Willy Tarreau <w@1wt.eu>
Cc: David Miller <davem@davemloft.net>,
herbert@gondor.apana.org.au, zbr@ioremap.net, jarkao2@gmail.com,
dada1@cosmosbay.com, ben@zeus.com, mingo@elte.hu,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
jens.axboe@oracle.com
Subject: Re: [PATCH v2] tcp: splice as many packets as possible at once
Date: Wed, 04 Feb 2009 11:19:06 -0800 [thread overview]
Message-ID: <ada63jqm2mt.fsf@cisco.com> (raw)
In-Reply-To: <20090204091217.GA21385@1wt.eu> (Willy Tarreau's message of "Wed, 4 Feb 2009 10:12:17 +0100")
> And the arbitrary choice of 9k for jumbo frames was total crap too.
> It's clear that no hardware designer was involved in the process.
> They have to stuff 16kB of RAM on a NIC to use only 9. And we need
> to allocate 3 pages for slightly more than 2. 7.5 kB would have been
> better in this regard.
9K was not totally arbitrary. The CRC used for checksumming ethernet
packets has a probability of undetected errors that goes up about
11-thousand something bytes. So the real limit is ~11000 bytes, and I
believe ~9000 was chosen to be able to carry 8K NFS payloads + all XDR
and transport headers without fragmentation.
- R.
next prev parent reply other threads:[~2009-02-04 19:19 UTC|newest]
Thread overview: 190+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-08 17:30 [PATCH] tcp: splice as many packets as possible at once Willy Tarreau
2009-01-08 19:44 ` Jens Axboe
2009-01-08 22:03 ` Willy Tarreau
2009-01-08 21:50 ` Ben Mansell
2009-01-08 21:55 ` David Miller
2009-01-08 22:20 ` Willy Tarreau
2009-01-13 23:08 ` David Miller
2009-01-09 6:47 ` Eric Dumazet
2009-01-09 7:04 ` Willy Tarreau
2009-01-09 7:28 ` Eric Dumazet
2009-01-09 7:42 ` Willy Tarreau
2009-01-13 23:27 ` David Miller
2009-01-13 23:35 ` Eric Dumazet
2009-01-09 15:42 ` Eric Dumazet
2009-01-09 17:57 ` Eric Dumazet
2009-01-09 18:54 ` Willy Tarreau
2009-01-09 20:51 ` Eric Dumazet
2009-01-09 21:24 ` Willy Tarreau
2009-01-09 22:02 ` Eric Dumazet
2009-01-09 22:09 ` Willy Tarreau
2009-01-09 22:07 ` Willy Tarreau
2009-01-09 22:12 ` Eric Dumazet
2009-01-09 22:17 ` Willy Tarreau
2009-01-09 22:42 ` Evgeniy Polyakov
2009-01-09 22:50 ` Willy Tarreau
2009-01-09 23:01 ` Evgeniy Polyakov
2009-01-09 23:06 ` Willy Tarreau
2009-01-10 7:40 ` Eric Dumazet
2009-01-11 12:58 ` Evgeniy Polyakov
2009-01-11 13:14 ` Eric Dumazet
2009-01-11 13:35 ` Evgeniy Polyakov
2009-01-11 16:00 ` Eric Dumazet
2009-01-11 16:05 ` Evgeniy Polyakov
2009-01-14 0:07 ` David Miller
2009-01-14 0:13 ` Evgeniy Polyakov
2009-01-14 0:16 ` David Miller
2009-01-14 0:22 ` Evgeniy Polyakov
2009-01-14 0:37 ` David Miller
2009-01-14 3:51 ` Herbert Xu
2009-01-14 4:25 ` David Miller
2009-01-14 7:27 ` David Miller
2009-01-14 8:26 ` Herbert Xu
2009-01-14 8:53 ` Jarek Poplawski
2009-01-14 9:29 ` David Miller
2009-01-14 9:42 ` Jarek Poplawski
2009-01-14 10:06 ` David Miller
2009-01-14 10:47 ` Jarek Poplawski
2009-01-14 11:29 ` Herbert Xu
2009-01-14 11:40 ` Jarek Poplawski
2009-01-14 11:45 ` Jarek Poplawski
2009-01-14 9:54 ` Jarek Poplawski
2009-01-14 10:01 ` Willy Tarreau
2009-01-14 12:06 ` Jarek Poplawski
2009-01-14 12:15 ` Jarek Poplawski
2009-01-14 11:28 ` Herbert Xu
2009-01-15 23:03 ` Willy Tarreau
2009-01-15 23:19 ` David Miller
2009-01-15 23:19 ` Herbert Xu
2009-01-15 23:26 ` David Miller
2009-01-15 23:32 ` Herbert Xu
2009-01-15 23:34 ` David Miller
2009-01-15 23:42 ` Willy Tarreau
2009-01-15 23:44 ` Willy Tarreau
2009-01-15 23:54 ` David Miller
2009-01-19 0:42 ` Willy Tarreau
2009-01-19 3:08 ` Herbert Xu
2009-01-19 3:27 ` David Miller
2009-01-19 6:14 ` Willy Tarreau
2009-01-19 6:19 ` David Miller
2009-01-19 6:45 ` Willy Tarreau
2009-01-19 10:19 ` Herbert Xu
2009-01-19 20:59 ` David Miller
2009-01-19 21:24 ` Herbert Xu
2009-01-25 21:03 ` Willy Tarreau
2009-01-26 7:59 ` Jarek Poplawski
2009-01-26 8:12 ` Willy Tarreau
2009-01-19 8:40 ` Jarek Poplawski
2009-01-19 3:28 ` David Miller
2009-01-19 6:11 ` Willy Tarreau
2009-01-24 21:23 ` Willy Tarreau
2009-01-20 12:01 ` Ben Mansell
2009-01-20 12:11 ` Evgeniy Polyakov
2009-01-20 13:43 ` Ben Mansell
2009-01-20 14:06 ` Jarek Poplawski
2009-01-16 6:51 ` Jarek Poplawski
2009-01-19 6:08 ` David Miller
2009-01-19 6:16 ` David Miller
2009-01-19 10:20 ` Herbert Xu
2009-01-20 8:37 ` Jarek Poplawski
2009-01-20 9:33 ` [PATCH v2] " Jarek Poplawski
2009-01-20 10:00 ` Evgeniy Polyakov
2009-01-20 10:20 ` Jarek Poplawski
2009-01-20 10:31 ` Evgeniy Polyakov
2009-01-20 11:01 ` Jarek Poplawski
2009-01-20 17:16 ` David Miller
2009-01-21 9:54 ` Jarek Poplawski
2009-01-22 9:04 ` [PATCH v3] " Jarek Poplawski
2009-01-26 5:22 ` David Miller
2009-01-27 7:11 ` Herbert Xu
2009-01-27 7:54 ` Jarek Poplawski
2009-01-27 10:09 ` Herbert Xu
2009-01-27 10:35 ` Jarek Poplawski
2009-01-27 10:57 ` Jarek Poplawski
2009-01-27 11:48 ` Herbert Xu
2009-01-27 12:16 ` Jarek Poplawski
2009-01-27 12:31 ` Jarek Poplawski
2009-01-27 17:06 ` David Miller
2009-01-28 8:10 ` Jarek Poplawski
2009-02-01 8:41 ` David Miller
2009-01-26 8:20 ` [PATCH v2] " Jarek Poplawski
2009-01-26 21:21 ` Evgeniy Polyakov
2009-01-27 6:10 ` David Miller
2009-01-27 7:40 ` Jarek Poplawski
2009-01-30 21:42 ` David Miller
2009-01-30 21:59 ` Willy Tarreau
2009-01-30 22:03 ` David Miller
2009-01-30 22:13 ` Willy Tarreau
2009-01-30 22:15 ` David Miller
2009-01-30 22:16 ` Herbert Xu
2009-02-02 8:08 ` Jarek Poplawski
2009-02-02 8:18 ` David Miller
2009-02-02 8:43 ` Jarek Poplawski
2009-02-03 7:50 ` David Miller
2009-02-03 9:41 ` Jarek Poplawski
2009-02-03 11:10 ` Evgeniy Polyakov
2009-02-03 11:24 ` Herbert Xu
2009-02-03 11:49 ` Evgeniy Polyakov
2009-02-03 11:53 ` Herbert Xu
2009-02-03 12:07 ` Evgeniy Polyakov
2009-02-03 12:12 ` Herbert Xu
2009-02-03 12:18 ` Evgeniy Polyakov
2009-02-03 12:25 ` Willy Tarreau
2009-02-03 12:28 ` Herbert Xu
2009-02-04 0:47 ` David Miller
2009-02-04 6:19 ` Willy Tarreau
2009-02-04 8:12 ` Evgeniy Polyakov
2009-02-04 8:54 ` Willy Tarreau
2009-02-04 8:59 ` Herbert Xu
2009-02-04 9:01 ` David Miller
2009-02-04 9:12 ` Willy Tarreau
2009-02-04 9:15 ` David Miller
2009-02-04 19:19 ` Roland Dreier [this message]
2009-02-04 19:28 ` Willy Tarreau
2009-02-04 19:48 ` Jarek Poplawski
2009-02-05 8:32 ` Bill Fink
2009-02-04 9:12 ` David Miller
2009-02-03 12:27 ` Herbert Xu
2009-02-03 13:05 ` david
2009-02-03 12:12 ` Evgeniy Polyakov
2009-02-03 12:18 ` Herbert Xu
2009-02-03 12:30 ` Evgeniy Polyakov
2009-02-03 12:33 ` Herbert Xu
2009-02-03 12:33 ` Nick Piggin
2009-02-04 0:46 ` David Miller
2009-02-04 9:41 ` Benny Amorsen
2009-02-04 12:01 ` Herbert Xu
2009-02-03 12:36 ` Jarek Poplawski
2009-02-03 13:06 ` Evgeniy Polyakov
2009-02-03 13:25 ` Jarek Poplawski
2009-02-03 14:20 ` Evgeniy Polyakov
2009-02-04 0:46 ` David Miller
2009-02-04 8:08 ` Evgeniy Polyakov
2009-02-04 9:23 ` Nick Piggin
2009-02-04 7:56 ` Jarek Poplawski
2009-02-06 7:52 ` David Miller
2009-02-06 8:09 ` Herbert Xu
2009-02-06 9:10 ` Jarek Poplawski
2009-02-06 9:17 ` David Miller
2009-02-06 9:42 ` Jarek Poplawski
2009-02-06 9:49 ` David Miller
2009-02-06 9:23 ` Herbert Xu
2009-02-06 9:51 ` Jarek Poplawski
2009-02-06 10:28 ` Herbert Xu
2009-02-06 10:58 ` Jarek Poplawski
2009-02-06 11:10 ` Willy Tarreau
2009-02-06 11:47 ` Jarek Poplawski
2009-02-06 18:59 ` Jarek Poplawski
2009-02-03 11:38 ` Nick Piggin
2009-01-27 18:42 ` David Miller
2009-01-15 23:32 ` [PATCH] " Willy Tarreau
2009-01-15 23:35 ` David Miller
2009-01-14 0:51 ` Herbert Xu
2009-01-14 1:24 ` David Miller
2009-01-09 22:45 ` Eric Dumazet
2009-01-09 22:53 ` Willy Tarreau
2009-01-09 23:34 ` Eric Dumazet
2009-01-13 5:45 ` David Miller
2009-01-14 0:05 ` David Miller
2009-01-13 23:31 ` David Miller
2009-01-13 23:26 ` David Miller
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