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From: David Miller <davem@davemloft.net>
To: johannes@sipsolutions.net
Cc: herbert@gondor.apana.org.au, dsd@gentoo.org,
	netdev@vger.kernel.org, linux-wireless@vger.kernel.org
Subject: Re: wireless vs. alignment requirements
Date: Sat, 24 Nov 2007 05:51:15 -0800 (PST)	[thread overview]
Message-ID: <20071124.055115.193713164.davem@davemloft.net> (raw)
In-Reply-To: <1195912176.4149.194.camel@johannes.berg>

From: Johannes Berg <johannes@sipsolutions.net>
Date: Sat, 24 Nov 2007 14:49:36 +0100

> 
> On Sat, 2007-11-24 at 21:32 +0800, Herbert Xu wrote:
> > On Sat, Nov 24, 2007 at 09:33:36AM +0100, Johannes Berg wrote:
> > >
> > > We still require four-byte alignment, no?
> > 
> > Not at all.  If NET_IP_ALIGN is zero then it won't be four-byte
> > aligned (since the Ethernet header is 14 bytes long).
> 
> Right. I just didn't think that would be a valid value for an
> architecture to set.

It is, and explicitly used by powerpc to get more of the
DMA transfers 64-byte aligned which is critical for
performance on some powerpc boxes.

  reply	other threads:[~2007-11-24 13:51 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-23  0:09 [PATCH] add compare_ether_addr_unaligned Daniel Drake
2007-11-23  4:11 ` Stephen Hemminger
2007-11-23 13:26 ` Herbert Xu
2007-11-26 10:39   ` Herbert Xu
2007-11-23 20:33 ` wireless vs. alignment requirements Johannes Berg
     [not found]   ` <1195850001.4149.165.camel-YfaajirXv214zXjbi5bjpg@public.gmane.org>
2007-11-24  6:15     ` Herbert Xu
2007-11-24  8:33       ` Johannes Berg
2007-11-24 13:32         ` Herbert Xu
     [not found]           ` <20071124133200.GA27531-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
2007-11-24 13:49             ` Johannes Berg
2007-11-24 13:51               ` David Miller [this message]
2007-11-24 14:13               ` Herbert Xu
     [not found]                 ` <20071124141319.GA27819-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
2007-11-24 20:11                   ` Stephen Hemminger
     [not found]                     ` <4748855C.5090103-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2007-11-24 21:33                       ` Johannes Berg
2007-11-25  1:08                       ` Herbert Xu
     [not found]                         ` <20071125010814.GD31668-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
2007-11-25 21:21                           ` Stephen Hemminger
     [not found]                             ` <4749E768.9040002-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2007-11-26  1:38                               ` Herbert Xu
2007-11-27 17:16                         ` H. Peter Anvin
2007-11-27 17:16                       ` H. Peter Anvin
     [not found]                         ` <474C50D7.5010901-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
2007-11-27 18:39                           ` Stephen Hemminger
     [not found]                             ` <20071127103940.314c7844-s08KbqtN0aBORcJjwVk881hTQxXnIo14@public.gmane.org>
2007-11-28  2:42                               ` H. Peter Anvin
2007-11-29 13:11                           ` Herbert Xu
2007-11-29 17:50                             ` H. Peter Anvin
2007-11-30  0:26                               ` Herbert Xu
     [not found]                                 ` <20071130002621.GI23769-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
2007-11-30  0:28                                   ` H. Peter Anvin
     [not found]                                     ` <474F5932.1030103-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
2007-11-30  0:34                                       ` Herbert Xu
     [not found]                                         ` <20071130003426.GJ23769-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
2007-11-30  0:41                                           ` H. Peter Anvin
2007-11-24 21:13                   ` Johannes Berg
     [not found]                     ` <1195938799.4149.197.camel-YfaajirXv214zXjbi5bjpg@public.gmane.org>
2007-11-25  1:44                       ` Herbert Xu
     [not found]                         ` <20071125014446.GA32104-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
2007-11-25 11:00                           ` Johannes Berg
     [not found]                             ` <1195988428.4149.225.camel-YfaajirXv214zXjbi5bjpg@public.gmane.org>
2007-11-25 11:22                               ` Herbert Xu
2007-11-25 13:54                                 ` Johannes Berg
     [not found]                                   ` <1195998864.4149.229.camel-YfaajirXv214zXjbi5bjpg@public.gmane.org>
2007-11-25 14:01                                     ` Herbert Xu
2007-11-25 17:04                                       ` Johannes Berg
     [not found]                                         ` <1196010257.4149.234.camel-YfaajirXv214zXjbi5bjpg@public.gmane.org>
2007-11-26  1:36                                           ` Herbert Xu
2007-11-24 13:11   ` Ulrich Kunitz

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