From: Lennert Buytenhek <buytenh@wantstofly.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>,
linux-arm-kernel@lists.infradead.org,
linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org,
linux-arch@vger.kernel.org,
'Kyungmin Park' <kyungmin.park@samsung.com>,
'Joerg Roedel' <joro@8bytes.org>,
'Russell King - ARM Linux' <linux@arm.linux.org.uk>
Subject: Re: [PATCH 3/8] ARM: dma-mapping: use asm-generic/dma-mapping-common.h
Date: Thu, 7 Jul 2011 14:09:18 +0200 [thread overview]
Message-ID: <20110707120918.GF7810@wantstofly.org> (raw)
In-Reply-To: <201106271519.43581.arnd@arndb.de>
On Mon, Jun 27, 2011 at 03:19:43PM +0200, Arnd Bergmann wrote:
> > > I suppose for the majority of the cases, the overhead of the indirect
> > > function call is near-zero, compared to the overhead of the cache
> > > management operation, so it would only make a difference for coherent
> > > systems without an IOMMU. Do we care about micro-optimizing those?
FWIW, when I was hacking on ARM access point routing performance some
time ago, turning the L1/L2 cache maintenance operations into inline
functions (inlined into the ethernet driver) gave me a significant and
measurable performance boost.
Such things can remain product-specific hacks, though.
> > Even in coherent case, the overhead caused by additional function call
> > should have really negligible impact on drivers performance.
>
> What about object code size? I guess since ixp23xx is the only platform
> that announces itself as coherent, we probably don't need to worry about
> it too much either. Lennert?
I don't think so. ixp23xx isn't a very popular platform anymore either,
having been discontinued some time ago.
thanks,
Lennert
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WARNING: multiple messages have this Message-ID (diff)
From: Lennert Buytenhek <buytenh@wantstofly.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>,
linux-arm-kernel@lists.infradead.org,
linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org,
linux-arch@vger.kernel.org,
'Kyungmin Park' <kyungmin.park@samsung.com>,
'Joerg Roedel' <joro@8bytes.org>,
'Russell King - ARM Linux' <linux@arm.linux.org.uk>
Subject: Re: [PATCH 3/8] ARM: dma-mapping: use asm-generic/dma-mapping-common.h
Date: Thu, 7 Jul 2011 14:09:18 +0200 [thread overview]
Message-ID: <20110707120918.GF7810@wantstofly.org> (raw)
Message-ID: <20110707120918.DmbEahADKiiTcUjN1Vc9HExvxpLyReT0p1WGHOtoIkg@z> (raw)
In-Reply-To: <201106271519.43581.arnd@arndb.de>
On Mon, Jun 27, 2011 at 03:19:43PM +0200, Arnd Bergmann wrote:
> > > I suppose for the majority of the cases, the overhead of the indirect
> > > function call is near-zero, compared to the overhead of the cache
> > > management operation, so it would only make a difference for coherent
> > > systems without an IOMMU. Do we care about micro-optimizing those?
FWIW, when I was hacking on ARM access point routing performance some
time ago, turning the L1/L2 cache maintenance operations into inline
functions (inlined into the ethernet driver) gave me a significant and
measurable performance boost.
Such things can remain product-specific hacks, though.
> > Even in coherent case, the overhead caused by additional function call
> > should have really negligible impact on drivers performance.
>
> What about object code size? I guess since ixp23xx is the only platform
> that announces itself as coherent, we probably don't need to worry about
> it too much either. Lennert?
I don't think so. ixp23xx isn't a very popular platform anymore either,
having been discontinued some time ago.
thanks,
Lennert
WARNING: multiple messages have this Message-ID (diff)
From: buytenh@wantstofly.org (Lennert Buytenhek)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/8] ARM: dma-mapping: use asm-generic/dma-mapping-common.h
Date: Thu, 7 Jul 2011 14:09:18 +0200 [thread overview]
Message-ID: <20110707120918.GF7810@wantstofly.org> (raw)
In-Reply-To: <201106271519.43581.arnd@arndb.de>
On Mon, Jun 27, 2011 at 03:19:43PM +0200, Arnd Bergmann wrote:
> > > I suppose for the majority of the cases, the overhead of the indirect
> > > function call is near-zero, compared to the overhead of the cache
> > > management operation, so it would only make a difference for coherent
> > > systems without an IOMMU. Do we care about micro-optimizing those?
FWIW, when I was hacking on ARM access point routing performance some
time ago, turning the L1/L2 cache maintenance operations into inline
functions (inlined into the ethernet driver) gave me a significant and
measurable performance boost.
Such things can remain product-specific hacks, though.
> > Even in coherent case, the overhead caused by additional function call
> > should have really negligible impact on drivers performance.
>
> What about object code size? I guess since ixp23xx is the only platform
> that announces itself as coherent, we probably don't need to worry about
> it too much either. Lennert?
I don't think so. ixp23xx isn't a very popular platform anymore either,
having been discontinued some time ago.
thanks,
Lennert
next prev parent reply other threads:[~2011-07-07 12:09 UTC|newest]
Thread overview: 201+ 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 ` Marek Szyprowski
2011-06-20 7:50 ` 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 7:50 ` Marek Szyprowski
2011-06-20 7:50 ` Marek Szyprowski
2011-06-20 8:35 ` Michal Nazarewicz
2011-06-20 8:35 ` Michal Nazarewicz
2011-06-20 8:35 ` Michal Nazarewicz
2011-06-20 10:46 ` Marek Szyprowski
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
2011-07-03 15:28 ` Russell King - ARM Linux
2011-07-26 12:56 ` Marek Szyprowski
2011-07-26 12:56 ` Marek Szyprowski
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 7:50 ` Marek Szyprowski
2011-06-20 7:50 ` Marek Szyprowski
2011-06-20 14:39 ` Russell King - ARM Linux
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
2011-06-20 15:15 ` Marek Szyprowski
2011-06-20 15:15 ` Marek Szyprowski
2011-06-24 15:24 ` Arnd Bergmann
2011-06-24 15:24 ` Arnd Bergmann
2011-06-24 15:24 ` Arnd Bergmann
2011-06-27 14:29 ` Marek Szyprowski
2011-06-27 14:29 ` Marek Szyprowski
2011-06-27 14:29 ` Marek Szyprowski
2011-06-27 14:53 ` Arnd Bergmann
2011-06-27 14:53 ` Arnd Bergmann
2011-06-27 14:53 ` Arnd Bergmann
2011-06-27 15:06 ` Marek Szyprowski
2011-06-27 15:06 ` Marek Szyprowski
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 7:50 ` Marek Szyprowski
2011-06-20 7:50 ` Marek Szyprowski
2011-06-20 14:33 ` [Linaro-mm-sig] " KyongHo Cho
2011-06-20 14:33 ` KyongHo Cho
2011-06-20 14:33 ` KyongHo Cho
2011-06-21 11:47 ` Marek Szyprowski
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 8:39 ` 'Joerg Roedel'
2011-06-24 15:36 ` Arnd Bergmann
2011-06-24 15:36 ` Arnd Bergmann
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 12:18 ` Marek Szyprowski
2011-06-27 13:19 ` Arnd Bergmann
2011-06-27 13:19 ` Arnd Bergmann
2011-06-27 13:19 ` Arnd Bergmann
2011-07-07 12:09 ` Lennert Buytenhek [this message]
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
2011-07-07 12:38 ` Russell King - ARM Linux
2011-07-15 0:10 ` Lennert Buytenhek
2011-07-15 0:10 ` Lennert Buytenhek
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 9:27 ` Russell King - ARM Linux
2011-07-15 21:53 ` Lennert Buytenhek
2011-07-15 21:53 ` Lennert Buytenhek
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 7:50 ` Marek Szyprowski
2011-06-20 14:37 ` KyongHo Cho
2011-06-20 14:37 ` KyongHo Cho
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 14:40 ` Russell King - ARM Linux
2011-06-20 15:23 ` Marek Szyprowski
2011-06-20 15:23 ` Marek Szyprowski
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 7:50 ` Marek Szyprowski
2011-06-20 7:50 ` Marek Szyprowski
2011-06-20 14:42 ` Russell King - ARM Linux
2011-06-20 14:42 ` Russell King - ARM Linux
2011-06-20 14:42 ` Russell King - ARM Linux
2011-06-20 15:31 ` Marek Szyprowski
2011-06-20 15:31 ` Marek Szyprowski
2011-06-20 15:31 ` Marek Szyprowski
2011-06-24 15:47 ` Arnd Bergmann
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
2011-06-27 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 ` Marek Szyprowski
2011-06-20 7:50 ` 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 7:50 ` Marek Szyprowski
2011-06-20 7:50 ` Marek Szyprowski
2011-06-20 14:45 ` KyongHo Cho
2011-06-20 14:45 ` KyongHo Cho
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 15:06 ` Russell King - ARM Linux
2011-06-20 15:06 ` Russell King - ARM Linux
2011-06-20 15:14 ` [Linaro-mm-sig] " KyongHo Cho
2011-06-20 15:14 ` KyongHo Cho
2011-06-20 15:14 ` KyongHo Cho
2011-06-21 11:23 ` Marek Szyprowski
2011-06-21 11:23 ` Marek Szyprowski
2011-06-21 11:23 ` Marek Szyprowski
2011-06-22 0:00 ` [Linaro-mm-sig] " KyongHo Cho
2011-06-22 0:00 ` KyongHo Cho
2011-06-22 0:00 ` KyongHo Cho
2011-06-24 7:20 ` Marek Szyprowski
2011-06-24 7:20 ` Marek Szyprowski
2011-06-24 7:20 ` Marek Szyprowski
2011-06-24 15:51 ` Arnd Bergmann
2011-06-24 15:51 ` Arnd Bergmann
2011-06-24 15:51 ` Arnd Bergmann
2011-06-24 16:15 ` James Bottomley
2011-06-24 16:15 ` James Bottomley
2011-06-24 16:15 ` James Bottomley
2011-06-24 16:23 ` Arnd Bergmann
2011-06-24 16:23 ` Arnd Bergmann
2011-06-24 16:23 ` Arnd Bergmann
2011-06-27 12:23 ` Marek Szyprowski
2011-06-27 12:23 ` Marek Szyprowski
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 13:22 ` Arnd Bergmann
2011-06-27 13:30 ` Marek Szyprowski
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
2011-06-24 15:53 ` Arnd Bergmann
2011-06-27 14:41 ` Marek Szyprowski
2011-06-27 14:41 ` Marek Szyprowski
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
2011-06-20 7:50 ` Marek Szyprowski
2011-06-20 7:50 ` Marek Szyprowski
2011-06-22 6:53 ` [Linaro-mm-sig] " KyongHo Cho
2011-06-22 6:53 ` KyongHo Cho
2011-06-22 6:53 ` KyongHo Cho
2011-06-22 4:53 ` [Linaro-mm-sig] [PATCH/RFC 0/8] ARM: DMA-mapping framework redesign Subash Patel
2011-06-22 4:53 ` Subash Patel
2011-06-22 4:53 ` Subash Patel
2011-06-22 6:59 ` Marek Szyprowski
2011-06-22 6:59 ` Marek Szyprowski
2011-06-22 6:59 ` Marek Szyprowski
2011-06-22 8:53 ` Subash Patel
2011-06-22 8:53 ` Subash Patel
2011-06-22 8:53 ` Subash Patel
2011-06-22 9:27 ` Marek Szyprowski
2011-06-22 9:27 ` Marek Szyprowski
2011-06-22 9:27 ` Marek Szyprowski
2011-06-22 16:00 ` Jordan Crouse
2011-06-22 16:00 ` Jordan Crouse
2011-06-22 16:00 ` Jordan Crouse
2011-06-23 13:09 ` Subash Patel
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 16:24 ` Michael K. Edwards
2011-06-23 16:24 ` Michael K. Edwards
2011-06-23 22:09 ` Michael K. Edwards
2011-06-23 22:09 ` Michael K. Edwards
2011-06-23 22:09 ` Michael K. Edwards
2011-06-25 5:23 ` Jonathan Morton
2011-06-25 5:23 ` Jonathan Morton
2011-06-25 5:23 ` Jonathan Morton
2011-06-25 9:55 ` Michael K. Edwards
2011-06-25 9:55 ` Michael K. Edwards
2011-06-25 9:55 ` Michael K. Edwards
2011-06-26 0:06 ` Jonathan Morton
2011-06-26 0:06 ` Jonathan Morton
2011-06-26 0:06 ` Jonathan Morton
2011-06-24 15:20 ` Arnd Bergmann
2011-06-24 15:20 ` Arnd Bergmann
2011-06-24 15:20 ` Arnd Bergmann
2011-06-24 9:18 ` Joerg Roedel
2011-06-24 9:18 ` Joerg Roedel
2011-06-24 9:18 ` Joerg Roedel
2011-06-24 14:26 ` Marek Szyprowski
2011-06-24 14:26 ` Marek Szyprowski
2011-06-24 14:26 ` Marek Szyprowski
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