From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Dan Malek <dan@embeddededge.com>
Cc: linuxppc-dev list <linuxppc-dev@ozlabs.org>,
linuxppc64-dev <linuxppc64-dev@ozlabs.org>
Subject: Re: [PATCH] powerpc: Merge align.c
Date: Wed, 16 Nov 2005 16:00:35 +1100 [thread overview]
Message-ID: <1132117236.5646.75.camel@gaston> (raw)
In-Reply-To: <02de724e66fe23fd23a3635c8b6f049f@embeddededge.com>
On Tue, 2005-11-15 at 23:26 -0500, Dan Malek wrote:
> On Nov 15, 2005, at 9:34 PM, Benjamin Herrenschmidt wrote:
>
> > What about lwz/stw cropssing page boundaries ? Is this handled in HW ?
>
> Yep. All of these hardware alignment support features on
> the Freescale processors are the reasons they are used
> so extensively in data communication processing (where
> unaligned data can sometimes occur). All of the load/store
> alignment issues are handled in the cache subsystem, so
> to the external world all you really see are cache line
> operations. In the event of uncached data operations, you
> get the performance penalty of two bus accesses, where
> some of the data is discarded.
Oh well, I suppose I'll have to dig out paulus' 601 based mac :)
Becky, can you send me a copy of your testcase ?
Ben.
next prev parent reply other threads:[~2005-11-16 5:00 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-14 8:00 [PATCH] powerpc: Merge align.c Benjamin Herrenschmidt
2005-11-14 19:53 ` Becky Bruce
2005-11-14 20:55 ` Benjamin Herrenschmidt
2005-11-15 5:10 ` Becky Bruce
2005-11-15 5:35 ` Benjamin Herrenschmidt
2005-11-16 2:19 ` Becky Bruce
2005-11-16 2:34 ` Benjamin Herrenschmidt
2005-11-16 3:23 ` Becky Bruce
2005-11-16 16:54 ` Andrey Volkov
2005-11-16 4:26 ` Dan Malek
2005-11-16 5:00 ` Benjamin Herrenschmidt [this message]
2005-11-16 5:35 ` Dan Malek
2005-11-16 6:13 ` Benjamin Herrenschmidt
2005-11-16 9:36 ` Gabriel Paubert
2005-11-16 15:15 ` Kumar Gala
2005-11-16 16:31 ` Becky Bruce
2005-11-16 19:24 ` Dan Malek
2005-11-16 19:20 ` Dan Malek
2005-11-16 19:45 ` Gabriel Paubert
2005-11-16 20:36 ` Dan Malek
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