linuxppc-dev.lists.ozlabs.org archive mirror
 help / color / mirror / Atom feed
From: Anton Vorontsov <avorontsov@mvista.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Matt Fleming <matt@console-pimps.org>,
	Albert Herranz <albert_herranz@yahoo.es>,
	linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linuxppc-dev@ozlabs.org, Ben Dooks <ben-linux@fluff.org>,
	Pierre Ossman <pierre@ossman.eu>
Subject: [PATCH 0/8] sdhci: Move real work out of an atomic context
Date: Wed, 14 Jul 2010 17:07:28 +0400	[thread overview]
Message-ID: <20100714130728.GA27339@oksana.dev.rtsoft.ru> (raw)

Hi all,

Currently the sdhci driver does everything in the atomic context.
And what is worse, PIO transfers are made from the IRQ handler.

This causes huge latencies (up to 120 ms). On some P2020 SOCs,
DMA and card detection is broken, which means that kernel polls
for the card via PIO transfers every second. Needless to say
that this is quite bad.

So, this patch set reworks sdhci code to avoid atomic context,
almost completely. We only do two device memory operations
in the atomic context, and all the rest is threaded.

I noticed no throughput drop neither with PIO transfers nor
with DMA (tested on MPC8569E CPU), while latencies should be
greatly improved.

Thanks,

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2

             reply	other threads:[~2010-07-14 13:07 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-14 13:07 Anton Vorontsov [this message]
2010-07-14 13:07 ` [PATCH 1/8] sdhci: Turn timeout timer into delayed work Anton Vorontsov
2010-07-14 13:07 ` [PATCH 2/8] sdhci: Use work structs instead of tasklets Anton Vorontsov
2010-07-14 13:08 ` [PATCH 3/8] sdhci: Clear interrupt status register just once Anton Vorontsov
2010-07-14 13:08 ` [PATCH 4/8] sdhci: Use threaded IRQ handler Anton Vorontsov
2010-07-14 13:08 ` [PATCH 5/8] sdhci: Turn host->lock into a mutex Anton Vorontsov
2010-07-14 13:08 ` [PATCH 6/8] sdhci: Get rid of card detect work Anton Vorontsov
2010-07-14 13:08 ` [PATCH 7/8] sdhci: Get rid of mdelay()s where it is safe and makes sense Anton Vorontsov
2010-07-14 13:08 ` [PATCH 8/8] sdhci: Use jiffies instead of a timeout counter Anton Vorontsov
2010-07-15  6:02 ` [PATCH 0/8] sdhci: Move real work out of an atomic context Matt Fleming
2010-07-21 21:13 ` Andrew Morton
2010-09-07 22:38 ` Andrew Morton
2010-09-08 21:37   ` Chris Ball
2010-09-08 21:57     ` Anton Vorontsov
2010-09-08 22:05       ` Chris Ball
2010-09-08 22:27         ` Anton Vorontsov
2010-09-09  2:28     ` Chris Ball
2010-09-09  7:15       ` Anton Vorontsov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20100714130728.GA27339@oksana.dev.rtsoft.ru \
    --to=avorontsov@mvista.com \
    --cc=akpm@linux-foundation.org \
    --cc=albert_herranz@yahoo.es \
    --cc=ben-linux@fluff.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mmc@vger.kernel.org \
    --cc=linuxppc-dev@ozlabs.org \
    --cc=matt@console-pimps.org \
    --cc=pierre@ossman.eu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).