From: Marc Gauthier <marc@tensilica.com>
To: Mike Frysinger <vapier.adi@gmail.com>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: "Johannes Weiner" <jw@emlix.com>,
"Christoph Lameter" <cl@linux.com>,
"Pekka Enberg" <penberg@cs.helsinki.fi>,
"Matt Mackall" <mpm@selenic.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Oskar Schirmer" <os@emlix.com>,
"Michael Hennerich" <Michael.Hennerich@analog.com>,
"linux-input@vger.kernel.org" <linux-input@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Daniel Glöckner" <dg@emlix.com>,
"Oliver Schneidewind" <osw@emlix.com>,
"Nick Piggin" <npiggin@suse.de>,
"David Rientjes" <rientjes@google.com>,
"David Brownell" <dbrownell@users.sourceforge.net>,
"Grant Likely" <grant.likely@secretlab.ca>,
"Chris Zankel" <chris@zankel.net>,
"Piet Delaney" <Piet.Delaney@tensilica.com>
Subject: RE: [LKML] Re: [PATCH v3] ad7877: keep dma rx buffers in seperate cache lines
Date: Tue, 11 May 2010 19:07:35 -0700 [thread overview]
Message-ID: <522C1DF17AF50042AD8AE87F7887BD3D0163549554@exch.hq.tensilica.com> (raw)
In-Reply-To: <AANLkTimm7bOmIz2sdODgHwtCk26kdHgZt7PvceM6gjS3@mail.gmail.com>
Mike Frysinger wrote:
> lets look at the cacheline sizes for arches that dont set
> ARCH_KMALLOC_MINALIGN to L1_CACHE_BYTES:
> - alplha - 32 or 64
> - frv - 32 or 64
> - blackfin - 32
> - parisc - 32 or 64
> - mn10300 - 16
> - s390 - 256
> - score - 16
> - sparc - 32
> - xtensa - 16 or 32
>
> assuming alpha and s390 handle cache coherency in hardware, it looks
> to me like the proposed assumption (kmalloc returns cachealigned
> pointers when cache management is in software) does not hold true.
>
> so should these other arches also be setting ARCH_KMALLOC_MINALIGN to
> L1_CACHE_BYTES ?
IMHO, yes. It just makes sense to avoid false-sharing issues, not to
allocate unrelated blocks in the same cache line.
Also as it turns out (hope he doesn't me telling), Christian Zankel
recently found a bug that was fixed exactly that way, by setting
ARCH_KMALLOC_MINALIGN to L1_CACHE_BYTES for the Xtensa architecture.
(Too recent to have percolated to mainline.)
A lot of the above might be cache line aligned (?).
-Marc
next prev parent reply other threads:[~2010-05-12 2:08 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-06 10:37 [PATCH] ad7877: fix spi word size to 16 bit Oskar Schirmer
2010-05-06 10:37 ` Oskar Schirmer
2010-05-06 10:37 ` [PATCH] ad7877: keep dma rx buffers in seperate cache lines Oskar Schirmer
2010-05-06 18:46 ` Mike Frysinger
2010-05-06 18:46 ` Mike Frysinger
2010-05-07 10:15 ` Oskar Schirmer
2010-05-07 10:15 ` Oskar Schirmer
2010-05-07 18:28 ` Mike Frysinger
2010-05-07 18:28 ` Mike Frysinger
2010-05-08 22:32 ` Johannes Weiner
2010-05-08 22:32 ` Johannes Weiner
2010-05-09 4:45 ` Mike Frysinger
2010-05-09 4:45 ` Mike Frysinger
2010-05-09 8:50 ` Oskar Schirmer
2010-05-09 8:50 ` Oskar Schirmer
2010-05-07 12:07 ` Johannes Weiner
2010-05-10 10:34 ` [PATCH v2] " Oskar Schirmer
2010-05-10 10:34 ` Oskar Schirmer
2010-05-10 10:42 ` [PATCH v3] " Oskar Schirmer
2010-05-10 10:42 ` Oskar Schirmer
2010-05-10 16:39 ` Mike Frysinger
2010-05-10 20:54 ` Dmitry Torokhov
2010-05-10 21:22 ` Andrew Morton
2010-05-10 21:27 ` Mike Frysinger
2010-05-11 6:05 ` Dmitry Torokhov
2010-05-11 6:05 ` Dmitry Torokhov
2010-05-11 6:11 ` Mike Frysinger
2010-05-11 6:11 ` Mike Frysinger
2010-05-11 3:20 ` Andrew Morton
2010-05-11 6:21 ` Dmitry Torokhov
2010-05-11 6:23 ` Mike Frysinger
2010-05-11 6:23 ` Mike Frysinger
2010-05-11 6:33 ` Dmitry Torokhov
2010-05-11 6:33 ` Dmitry Torokhov
2010-05-11 6:37 ` Mike Frysinger
2010-05-11 6:42 ` Pekka Enberg
2010-05-11 13:57 ` Christoph Lameter
2010-05-11 16:52 ` Dmitry Torokhov
2010-05-11 17:31 ` Mike Frysinger
2010-05-11 18:59 ` Pekka Enberg
2010-05-11 20:03 ` Mike Frysinger
2010-05-11 20:07 ` Matt Mackall
2010-05-11 20:10 ` Mike Frysinger
2010-05-11 20:10 ` Mike Frysinger
2010-05-11 20:21 ` Christoph Lameter
2010-05-11 20:34 ` Mike Frysinger
2010-05-11 20:38 ` Pekka Enberg
2010-05-11 20:43 ` Mike Frysinger
2010-05-11 20:43 ` Mike Frysinger
2010-05-11 20:47 ` Pekka Enberg
2010-05-13 6:21 ` Paul Mundt
2010-05-11 20:46 ` Christoph Lameter
2010-05-11 20:54 ` Mike Frysinger
2010-05-11 20:54 ` Mike Frysinger
2010-05-11 21:01 ` Pekka Enberg
2010-05-11 21:11 ` Mike Frysinger
2010-05-11 21:11 ` Mike Frysinger
2010-05-12 1:58 ` FUJITA Tomonori
[not found] ` <20100511214836.GH1726@emlix.com>
2010-05-11 21:53 ` Dmitry Torokhov
2010-05-11 22:39 ` Mike Frysinger
2010-05-11 22:39 ` Mike Frysinger
2010-05-12 2:07 ` Marc Gauthier [this message]
2010-05-12 3:03 ` [LKML] " Nick Piggin
2010-05-12 3:23 ` FUJITA Tomonori
2010-05-12 4:35 ` Mike Frysinger
2010-05-12 4:35 ` Mike Frysinger
2010-05-12 5:28 ` FUJITA Tomonori
2010-05-12 5:28 ` FUJITA Tomonori
2010-05-12 14:37 ` Mike Frysinger
2010-05-12 14:37 ` Mike Frysinger
2010-05-12 18:11 ` Dmitry Torokhov
2010-05-12 18:28 ` Mike Frysinger
2010-05-12 18:28 ` Mike Frysinger
2010-05-12 10:36 ` Johannes Weiner
2010-05-12 12:35 ` Marc Gauthier
2010-05-12 14:36 ` Mike Frysinger
2010-05-12 14:36 ` Mike Frysinger
2010-05-19 12:48 ` David Woodhouse
2010-05-19 13:07 ` Nick Piggin
2010-05-19 13:17 ` David Woodhouse
2010-05-19 13:36 ` Nick Piggin
2010-05-19 13:44 ` Johannes Weiner
2010-05-19 13:52 ` Nick Piggin
2010-05-19 14:38 ` FUJITA Tomonori
2010-05-19 14:58 ` David Woodhouse
2010-05-20 4:42 ` FUJITA Tomonori
2010-05-19 16:37 ` Dmitry Torokhov
2010-05-19 15:00 ` Johannes Weiner
2010-05-17 6:12 ` Michal Simek
2010-05-19 13:00 ` David Woodhouse
2010-05-11 22:37 ` Alan Cox
2010-05-11 20:22 ` Pekka Enberg
2010-05-11 14:12 ` Oskar Schirmer
2010-05-11 14:12 ` Oskar Schirmer
2010-05-06 11:18 ` [PATCH] ad7877: fix spi word size to 16 bit Hennerich, Michael
2010-05-06 11:18 ` Hennerich, Michael
2010-05-06 18:26 ` Mike Frysinger
2010-05-06 18:26 ` Mike Frysinger
2010-05-07 9:41 ` Daniel Glöckner
2010-05-07 9:41 ` Daniel Glöckner
2010-05-07 18:23 ` Mike Frysinger
2010-05-07 18:23 ` Mike Frysinger
2010-05-13 7:53 ` Dmitry Torokhov
2010-05-13 7:53 ` Dmitry Torokhov
2010-05-15 18:15 ` Oskar Schirmer
2010-05-15 18:15 ` Oskar Schirmer
2010-05-16 19:25 ` Mike Frysinger
2010-05-16 19:25 ` Mike Frysinger
2010-05-17 7:29 ` Oskar Schirmer
2010-05-17 7:29 ` Oskar Schirmer
2010-05-17 8:14 ` Hennerich, Michael
2010-05-17 8:14 ` Hennerich, Michael
2010-05-17 8:41 ` Oskar Schirmer
2010-05-17 8:41 ` Oskar Schirmer
2010-05-17 23:49 ` Mike Frysinger
2010-05-17 23:49 ` Mike Frysinger
2010-05-18 0:18 ` H Hartley Sweeten
2010-05-18 0:18 ` H Hartley Sweeten
2010-05-18 8:32 ` Oskar Schirmer
2010-05-18 8:32 ` Oskar Schirmer
2010-05-18 9:37 ` Daniel Glöckner
2010-05-18 9:37 ` Daniel Glöckner
2010-05-18 8:34 ` [PATCH v2] " Oskar Schirmer
2010-05-18 8:34 ` Oskar Schirmer
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