From: "David S. Miller" <davem@redhat.com>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: alan@lxorguk.ukuu.org.uk, davidm@hpl.hp.com,
davidm@napali.hpl.hp.com, peter@chubb.wattle.id.au,
bcrl@kvack.org, ak@suse.de, iod00d@hp.com,
peterc@gelato.unsw.edu.au, linux-ns83820@kvack.org,
linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: NS83820 2.6.0-test5 driver seems unstable on IA64
Date: Tue, 23 Sep 2003 16:32:52 -0700 [thread overview]
Message-ID: <20030923163252.2a93e406.davem@redhat.com> (raw)
In-Reply-To: <DD755978BA8283409FB0087C39132BD101B01197@fmsmsx404.fm.intel.com>
On Tue, 23 Sep 2003 15:58:29 -0700
"Luck, Tony" <tony.luck@intel.com> wrote:
> Which is great until the "cleverly written" program is fed a data set
> that pushes into the unaligned case far more frequently than the
> programmer anticipated.
Which is why the people who work on the networking are well
aware of the issues and will make sure the common case never
triggers these unaligned accesses.
People writing protocol stacks _don't_ feed these data unaligned
cases out onto the wire, because like us they want the networking
to go fast. Why in the world do you think they specify in the
very RFCs that define the protocols that one should use NOP options
in the TCP option area in order to align TCP timestamps on a 32-bit
boundry?
Do you think they say this so people can go ahead and use memmove()'s
and byte loads all over the place anyways?
No, rather, they specify things so that unless you do something
absolutely stupid all the shit is aligned properly.
It is absurdly stupid to do byte loads of TCP and IP header
bits just because one tenth of one hundredths of one percent
of systems have some configuration where word and half-word
loads of these things will be unaligned _AND_ be slow on that
cpu.
next prev parent reply other threads:[~2003-09-23 23:45 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-23 22:58 NS83820 2.6.0-test5 driver seems unstable on IA64 Luck, Tony
2003-09-23 23:32 ` David S. Miller [this message]
2003-09-24 5:18 ` Valdis.Kletnieks
[not found] <A4gy.8wi.13@gated-at.bofh.it>
[not found] ` <A4gy.8wi.15@gated-at.bofh.it>
[not found] ` <A4gy.8wi.17@gated-at.bofh.it>
[not found] ` <A4gy.8wi.11@gated-at.bofh.it>
[not found] ` <A4Tv.Ud.37@gated-at.bofh.it>
[not found] ` <AepM.5Zb.41@gated-at.bofh.it>
2003-09-27 4:26 ` Andi Kleen
2003-09-27 4:34 ` David Mosberger
2003-09-27 23:36 ` David S. Miller
[not found] <A2yd.64p.31@gated-at.bofh.it>
[not found] ` <A2yd.64p.29@gated-at.bofh.it>
[not found] ` <A317.6GH.7@gated-at.bofh.it>
2003-09-26 17:04 ` Andi Kleen
2003-09-26 17:22 ` Chris Friesen
2003-09-26 17:47 ` David Mosberger
2003-09-27 3:57 ` David S. Miller
2003-09-27 4:36 ` Andi Kleen
2003-09-27 4:52 ` David Mosberger
[not found] <zU7D.2Ji.27@gated-at.bofh.it>
2003-09-26 15:14 ` Andi Kleen
2003-09-26 15:41 ` David Mosberger
-- strict thread matches above, loose matches on Subject: below --
2003-09-26 6:16 Manfred Spraul
2003-09-26 6:07 ` David S. Miller
2003-09-26 6:41 ` David Mosberger
2003-09-26 14:38 ` Ivan Kokshaysky
2003-09-27 3:12 ` David S. Miller
2003-09-23 18:21 Luck, Tony
2003-09-23 18:29 ` Benjamin LaHaise
2003-09-23 18:45 ` David S. Miller
2003-09-23 18:51 ` Grant Grundler
2003-09-23 18:51 ` David S. Miller
2003-09-23 20:38 ` Grant Grundler
2003-09-23 20:45 ` David S. Miller
2003-09-23 22:35 ` Grant Grundler
2003-09-23 23:35 ` David S. Miller
2003-09-24 0:13 ` Grant Grundler
2003-09-24 0:04 ` David S. Miller
2003-09-24 1:58 ` William Lee Irwin III
2003-09-23 19:04 ` Benjamin LaHaise
2003-09-23 18:54 ` Andreas Schwab
2003-09-23 18:52 ` David S. Miller
2003-09-23 19:09 ` Andreas Schwab
2003-09-23 19:01 ` David S. Miller
2003-09-23 19:16 ` Andreas Schwab
2003-09-23 19:08 ` David S. Miller
2003-09-23 19:28 ` Matthew Wilcox
2003-09-23 19:22 ` David S. Miller
2003-09-23 23:15 ` Andrew Morton
2003-09-23 23:37 ` David S. Miller
2003-09-24 0:14 ` Matthew Wilcox
2003-09-24 0:06 ` David S. Miller
2003-09-23 19:10 ` Jeff Garzik
2003-09-23 19:11 ` Benjamin LaHaise
2003-09-23 19:22 ` Jeff Garzik
2003-09-23 21:00 ` Alan Cox
2003-09-23 21:16 ` David Mosberger
2003-09-24 1:47 ` David S. Miller
2003-09-23 17:58 Van Maren, Kevin
2003-09-23 17:57 ` David S. Miller
2003-09-23 18:27 ` David Mosberger
2003-09-23 18:47 ` David S. Miller
2003-09-23 19:17 ` David Mosberger
2003-09-23 19:10 ` David S. Miller
2003-09-23 20:00 ` David Mosberger
2003-09-24 3:08 ` David S. Miller
2003-09-25 16:11 ` Ivan Kokshaysky
2003-09-26 1:12 ` David S. Miller
2003-09-23 18:06 ` David Mosberger
2003-09-23 19:11 ` David S. Miller
2003-09-19 4:16 Peter Chubb
2003-09-19 4:38 ` Grant Grundler
2003-09-19 4:43 ` Andi Kleen
2003-09-19 5:01 ` Peter Chubb
2003-09-19 5:53 ` Andi Kleen
2003-09-19 10:49 ` Benjamin LaHaise
2003-09-23 0:34 ` Peter Chubb
2003-09-23 0:36 ` Benjamin LaHaise
2003-09-23 6:22 ` David S. Miller
2003-09-23 10:40 ` Peter Chubb
2003-09-23 10:51 ` David S. Miller
2003-09-23 14:59 ` David Mosberger
2003-09-23 17:27 ` David S. Miller
2003-09-23 17:56 ` David Mosberger
2003-09-24 2:55 ` David S. Miller
2003-09-23 23:04 ` Ian Wienand
2003-09-23 23:35 ` David S. Miller
2003-09-19 5:04 ` Grant Grundler
2003-09-19 5:11 ` Peter Chubb
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