From: pavel@ucw.cz (Pavel Machek)
To: linux-arm-kernel@lists.infradead.org
Subject: MMC quirks relating to performance/lifetime.
Date: Fri, 11 Feb 2011 15:41:39 +0100 [thread overview]
Message-ID: <20110211144139.GC3920@ucw.cz> (raw)
In-Reply-To: <AANLkTikh4vfS7SLKAa-aUXhbTxcHzYHmBuaXj1qHHYN9@mail.gmail.com>
Hi!
> I'm not sure if this is the best place to bring this up, but Russel's
> name is on a fair share of drivers/mmc code, and there does seem to be
> quite a bit of MMC-related discussions. Excuse me in advance if this
> isn't the right forum :-).
>
> Certain MMC vendors (maybe even quite a bit of them) use a pretty
> rigid buffering scheme when it comes to handling writes. There is
> usually a buffer A for random accesses, and a buffer B for sequential
> accesses. For certain Toshiba parts, it looks like buffer A is 8KB
> wide, with buffer B being 4MB wide, and all accesses larger than 8KB
> effectively equating to 4MB accesses. Worse, consecutive small (8k)
> writes are treated as one large sequential access, once again ending
> up in buffer B, thus necessitating out-of-order writing to work around
> this.
Hmmmm, I somehow assumed MMCs would be much more cleverr than this.
> reorders) them? The thresholds would then be adjustable as
> module/kernel parameters based on manfid. I'm asking because I have a
> patch now, but its ugly and hardcoded against a specific manufacturer.
How big is performance difference?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2011-02-11 14:41 UTC|newest]
Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-08 21:22 MMC quirks relating to performance/lifetime Andrei Warkentin
2011-02-08 21:38 ` Wolfram Sang
2011-02-08 21:38 ` Wolfram Sang
2011-02-08 22:42 ` Russell King - ARM Linux
2011-02-09 8:37 ` Linus Walleij
2011-02-09 8:37 ` Linus Walleij
2011-02-09 9:13 ` Arnd Bergmann
2011-02-09 9:13 ` Arnd Bergmann
2011-02-11 22:33 ` Andrei Warkentin
2011-02-11 22:33 ` Andrei Warkentin
2011-02-12 17:05 ` Arnd Bergmann
2011-02-12 17:05 ` Arnd Bergmann
2011-02-12 17:33 ` Andrei Warkentin
2011-02-12 17:33 ` Andrei Warkentin
2011-02-12 18:22 ` Arnd Bergmann
2011-02-12 18:22 ` Arnd Bergmann
2011-02-18 1:10 ` Andrei Warkentin
2011-02-18 1:10 ` Andrei Warkentin
2011-02-18 13:44 ` Arnd Bergmann
2011-02-18 13:44 ` Arnd Bergmann
2011-02-18 19:47 ` Andrei Warkentin
2011-02-18 19:47 ` Andrei Warkentin
2011-02-18 22:40 ` Andrei Warkentin
2011-02-18 22:40 ` Andrei Warkentin
2011-02-18 23:17 ` Andrei Warkentin
2011-02-18 23:17 ` Andrei Warkentin
2011-02-19 11:20 ` Arnd Bergmann
2011-02-19 11:20 ` Arnd Bergmann
2011-02-20 5:56 ` Andrei Warkentin
2011-02-20 5:56 ` Andrei Warkentin
2011-02-20 15:23 ` Arnd Bergmann
2011-02-20 15:23 ` Arnd Bergmann
2011-02-22 7:05 ` Andrei Warkentin
2011-02-22 7:05 ` Andrei Warkentin
2011-02-22 16:49 ` Arnd Bergmann
2011-02-22 16:49 ` Arnd Bergmann
2011-02-19 9:54 ` Arnd Bergmann
2011-02-19 9:54 ` Arnd Bergmann
2011-02-20 4:39 ` Andrei Warkentin
2011-02-20 4:39 ` Andrei Warkentin
2011-02-20 15:03 ` Arnd Bergmann
2011-02-20 15:03 ` Arnd Bergmann
2011-02-22 6:42 ` Andrei Warkentin
2011-02-22 6:42 ` Andrei Warkentin
2011-02-22 16:42 ` Arnd Bergmann
2011-02-22 16:42 ` Arnd Bergmann
2011-02-11 23:23 ` Linus Walleij
2011-02-11 23:23 ` Linus Walleij
2011-02-12 10:45 ` Arnd Bergmann
2011-02-12 10:45 ` Arnd Bergmann
2011-02-12 10:59 ` Russell King - ARM Linux
2011-02-12 10:59 ` Russell King - ARM Linux
2011-02-12 16:28 ` Arnd Bergmann
2011-02-12 16:28 ` Arnd Bergmann
2011-02-12 16:37 ` Russell King - ARM Linux
2011-02-12 16:37 ` Russell King - ARM Linux
2011-02-11 22:27 ` Andrei Warkentin
2011-02-11 22:27 ` Andrei Warkentin
2011-02-12 18:37 ` Arnd Bergmann
2011-02-12 18:37 ` Arnd Bergmann
2011-02-13 0:10 ` Andrei Warkentin
2011-02-13 0:10 ` Andrei Warkentin
2011-02-13 17:39 ` Arnd Bergmann
2011-02-13 17:39 ` Arnd Bergmann
2011-02-14 19:29 ` Andrei Warkentin
2011-02-14 19:29 ` Andrei Warkentin
2011-02-14 20:22 ` Arnd Bergmann
2011-02-14 20:22 ` Arnd Bergmann
2011-02-14 22:25 ` Andrei Warkentin
2011-02-14 22:25 ` Andrei Warkentin
2011-02-15 17:16 ` Arnd Bergmann
2011-02-15 17:16 ` Arnd Bergmann
2011-02-17 2:08 ` Andrei Warkentin
2011-02-17 2:08 ` Andrei Warkentin
2011-02-17 15:47 ` Arnd Bergmann
2011-02-17 15:47 ` Arnd Bergmann
2011-02-20 11:27 ` Andrei Warkentin
2011-02-20 11:27 ` Andrei Warkentin
2011-02-20 14:39 ` Arnd Bergmann
2011-02-20 14:39 ` Arnd Bergmann
2011-02-22 7:46 ` Andrei Warkentin
2011-02-22 7:46 ` Andrei Warkentin
2011-02-22 17:00 ` Arnd Bergmann
2011-02-22 17:00 ` Arnd Bergmann
2011-02-23 10:19 ` Andrei Warkentin
2011-02-23 10:19 ` Andrei Warkentin
2011-02-23 16:09 ` Arnd Bergmann
2011-02-23 16:09 ` Arnd Bergmann
2011-02-23 22:26 ` Andrei Warkentin
2011-02-23 22:26 ` Andrei Warkentin
2011-02-24 9:24 ` Arnd Bergmann
2011-02-24 9:24 ` Arnd Bergmann
2011-02-25 11:02 ` Andrei Warkentin
2011-02-25 11:02 ` Andrei Warkentin
2011-02-25 12:21 ` Arnd Bergmann
2011-02-25 12:21 ` Arnd Bergmann
2011-03-01 18:48 ` Jens Axboe
2011-03-01 18:48 ` Jens Axboe
2011-03-01 19:11 ` Arnd Bergmann
2011-03-01 19:11 ` Arnd Bergmann
2011-03-01 19:15 ` Jens Axboe
2011-03-01 19:15 ` Jens Axboe
2011-03-01 19:51 ` Arnd Bergmann
2011-03-01 19:51 ` Arnd Bergmann
2011-03-01 21:33 ` Andrei Warkentin
2011-03-01 21:33 ` Andrei Warkentin
2011-03-02 10:34 ` Andrei Warkentin
2011-03-02 10:34 ` Andrei Warkentin
2011-03-05 9:23 ` Andrei Warkentin
2011-03-05 9:23 ` Andrei Warkentin
2011-02-11 14:41 ` Pavel Machek [this message]
2011-02-11 14:51 ` Arnd Bergmann
2011-02-11 15:20 ` Lei Wen
2011-02-11 15:25 ` Arnd Bergmann
2011-03-08 6:59 ` Pavel Machek
2011-03-08 14:03 ` Arnd Bergmann
2011-03-08 14:03 ` Arnd Bergmann
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