From: "Michael K. Edwards" <m.k.edwards@gmail.com>
To: Jonathan Morton <jonathan.morton@movial.com>
Cc: Subash Patel <subashrp@gmail.com>,
Jordan Crouse <jcrouse@codeaurora.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
linux-arch@vger.kernel.org, linaro-mm-sig@lists.linaro.org,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org
Subject: Re: [Linaro-mm-sig] [PATCH/RFC 0/8] ARM: DMA-mapping framework redesign
Date: Thu, 23 Jun 2011 15:09:55 -0700 [thread overview]
Message-ID: <BANLkTimi2FAmcb7ZWnjRqb-Cb8acXWsCTw@mail.gmail.com> (raw)
In-Reply-To: <BANLkTikzTwNvaaUSk26qzONemogBAGuBRg@mail.gmail.com>
Jonathan -
I'm inviting you to this conversation (and to linaro-mm-sig, if you'd
care to participate!), because I'd really like your commentary on what
it takes to make write-combining fully effective on various ARMv7
implementations.
The current threads:
http://lists.linaro.org/pipermail/linaro-mm-sig/2011-June/000334.html
http://lists.linaro.org/pipermail/linaro-mm-sig/2011-June/000263.html
Archive link for a related discussion:
http://lists.linaro.org/pipermail/linaro-mm-sig/2011-April/000003.html
Getting full write-combining performance on Intel architectures
involves a somewhat delicate dance:
http://software.intel.com/en-us/articles/copying-accelerated-video-decode-frame-buffers/
And I expect something similar to be necessary in order to avoid the
read-modify-write penalty for write-combining buffers on ARMv7. (NEON
store-multiple operations can fill an entire 64-byte entry in the
victim buffer in one opcode; I don't know whether this is enough to
stop the L3 memory system from reading the data before clobbering it.)
Cheers,
- Michael
next prev parent reply other threads:[~2011-06-23 22:09 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-20 7:50 [PATCH/RFC 0/8] ARM: DMA-mapping framework redesign Marek Szyprowski
2011-06-20 7:50 ` [PATCH 1/8] ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops Marek Szyprowski
2011-06-20 8:35 ` Michal Nazarewicz
2011-06-20 10:46 ` Marek Szyprowski
2011-06-20 10:46 ` Marek Szyprowski
2011-07-03 15:28 ` Russell King - ARM Linux
2011-07-03 15:28 ` Russell King - ARM Linux
2011-07-26 12:56 ` Marek Szyprowski
2011-06-20 7:50 ` [PATCH 2/8] ARM: dma-mapping: implement dma_map_single on top of dma_map_page Marek Szyprowski
2011-06-20 14:39 ` Russell King - ARM Linux
2011-06-20 14:39 ` Russell King - ARM Linux
2011-06-20 15:15 ` Marek Szyprowski
2011-06-24 15:24 ` Arnd Bergmann
2011-06-24 15:24 ` Arnd Bergmann
2011-06-27 14:29 ` Marek Szyprowski
2011-06-27 14:53 ` Arnd Bergmann
2011-06-27 14:53 ` Arnd Bergmann
2011-06-27 15:06 ` Marek Szyprowski
2011-06-20 7:50 ` [PATCH 3/8] ARM: dma-mapping: use asm-generic/dma-mapping-common.h Marek Szyprowski
2011-06-20 14:33 ` [Linaro-mm-sig] " KyongHo Cho
2011-06-21 11:47 ` Marek Szyprowski
2011-06-21 11:47 ` Marek Szyprowski
2011-06-24 8:39 ` 'Joerg Roedel'
2011-06-24 8:39 ` 'Joerg Roedel'
2011-06-24 15:36 ` Arnd Bergmann
2011-06-24 15:36 ` Arnd Bergmann
2011-06-27 12:18 ` Marek Szyprowski
2011-06-27 12:18 ` Marek Szyprowski
2011-06-27 13:19 ` Arnd Bergmann
2011-06-27 13:19 ` Arnd Bergmann
2011-07-07 12:09 ` Lennert Buytenhek
2011-07-07 12:09 ` Lennert Buytenhek
2011-07-07 12:38 ` Russell King - ARM Linux
2011-07-07 12:38 ` Russell King - ARM Linux
2011-07-15 0:10 ` Lennert Buytenhek
2011-07-15 9:27 ` Russell King - ARM Linux
2011-07-15 9:27 ` Russell King - ARM Linux
2011-07-15 21:53 ` Lennert Buytenhek
2011-06-20 7:50 ` [PATCH 4/8] ARM: dma-mapping: implement dma sg methods on top of generic dma ops Marek Szyprowski
2011-06-20 7:50 ` Marek Szyprowski
2011-06-20 14:37 ` KyongHo Cho
2011-06-20 14:40 ` Russell King - ARM Linux
2011-06-20 14:40 ` Russell King - ARM Linux
2011-06-20 15:23 ` Marek Szyprowski
2011-06-20 7:50 ` [PATCH 5/8] ARM: dma-mapping: move all dma bounce code to separate dma ops structure Marek Szyprowski
2011-06-20 14:42 ` Russell King - ARM Linux
2011-06-20 15:31 ` Marek Szyprowski
2011-06-20 15:31 ` Marek Szyprowski
2011-06-24 15:47 ` Arnd Bergmann
2011-06-24 15:47 ` Arnd Bergmann
2011-06-27 14:20 ` Marek Szyprowski
2011-06-27 14:20 ` Marek Szyprowski
2011-06-20 7:50 ` [PATCH 6/8] ARM: dma-mapping: remove redundant code and cleanup Marek Szyprowski
2011-06-20 7:50 ` [PATCH 7/8] common: dma-mapping: change alloc/free_coherent method to more generic alloc/free_attrs Marek Szyprowski
2011-06-20 14:45 ` KyongHo Cho
2011-06-20 15:06 ` Russell King - ARM Linux
2011-06-20 15:06 ` Russell King - ARM Linux
2011-06-20 15:14 ` [Linaro-mm-sig] " KyongHo Cho
2011-06-21 11:23 ` Marek Szyprowski
2011-06-22 0:00 ` [Linaro-mm-sig] " KyongHo Cho
2011-06-24 7:20 ` Marek Szyprowski
2011-06-24 15:51 ` Arnd Bergmann
2011-06-24 15:51 ` Arnd Bergmann
2011-06-24 16:15 ` James Bottomley
2011-06-24 16:23 ` Arnd Bergmann
2011-06-27 12:23 ` Marek Szyprowski
2011-06-27 12:23 ` Marek Szyprowski
2011-06-27 13:22 ` Arnd Bergmann
2011-06-27 13:22 ` Arnd Bergmann
2011-06-27 13:30 ` Marek Szyprowski
2011-06-27 13:30 ` Marek Szyprowski
2011-06-24 15:53 ` Arnd Bergmann
2011-06-24 15:53 ` Arnd Bergmann
2011-06-27 14:41 ` Marek Szyprowski
2011-06-20 7:50 ` [PATCH 8/8] ARM: dma-mapping: use alloc, mmap, free from dma_ops Marek Szyprowski
2011-06-22 6:53 ` [Linaro-mm-sig] " KyongHo Cho
2011-06-22 4:53 ` [Linaro-mm-sig] [PATCH/RFC 0/8] ARM: DMA-mapping framework redesign Subash Patel
2011-06-22 6:59 ` Marek Szyprowski
2011-06-22 6:59 ` Marek Szyprowski
2011-06-22 8:53 ` Subash Patel
2011-06-22 9:27 ` Marek Szyprowski
2011-06-22 16:00 ` Jordan Crouse
2011-06-23 13:09 ` Subash Patel
2011-06-23 13:09 ` Subash Patel
2011-06-23 16:24 ` Michael K. Edwards
2011-06-23 22:09 ` Michael K. Edwards [this message]
2011-06-25 5:23 ` Jonathan Morton
2011-06-25 5:23 ` Jonathan Morton
2011-06-25 9:55 ` Michael K. Edwards
2011-06-26 0:06 ` Jonathan Morton
2011-06-24 15:20 ` Arnd Bergmann
2011-06-24 15:20 ` Arnd Bergmann
2011-06-24 9:18 ` Joerg Roedel
2011-06-24 14:26 ` Marek Szyprowski
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