From: Jeff Garzik <jgarzik@pobox.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>,
James Bottomley <James.Bottomley@suse.de>,
Catalin Marinas <catalin.marinas@arm.com>,
David Miller <davem@davemloft.net>,
jeff@garzik.org, linux-ide@vger.kernel.org, stable@kernel.org,
tj@kernel.org
Subject: Re: [patch for 2.6.33? 1/1] ata: call flush_dcache_page() around PIO data transfers in libata-aff.c
Date: Wed, 03 Feb 2010 13:12:07 -0500 [thread overview]
Message-ID: <4B69BC77.4040907@pobox.com> (raw)
In-Reply-To: <20100203180049.4aa066ad@lxorguk.ukuu.org.uk>
On 02/03/2010 01:00 PM, Alan Cox wrote:
> On Wed, 03 Feb 2010 12:52:34 -0500
> Jeff Garzik<jgarzik@pobox.com> wrote:
>
>> On 02/03/2010 12:46 PM, Alan Cox wrote:
>>> And indeed there was a patch I proposed in 2008 for this bounce
>>> buffer latency: See the archive
>>>
>>> Date: Fri, 29 Feb 2008 13:51:06 +0000
>>> From: Alan Cox<alan@lxorguk.ukuu.org.uk>
>>> To: linux-ide@vger.kernel.org, jeff@garzik.org
>>> Subject: [RFC PATCH] libata: PIO via bounce buffer
>>>
>>> although it doesn't deal with the dcache coherency issue and seems to
>>> need a little tweaking to apply due to other changes
>>
>> Yeah, I definitely liked the idea. I wonder if we could do the
>> allocation during port_start rather than at the time of bounce?
>
> I actually got better numbers using kmalloc - no idea why - perhaps we
> get a hot page ?
Seems logical. It surprises me, though, that being lockless and
completely avoiding the kmalloc infrastructure wasn't a bigger win. Was
this measured on UP?
If your approach has the lowest cost, let's get it in... I like
decisions informed by hard data. :)
Jeff
next prev parent reply other threads:[~2010-02-03 18:12 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-02 22:11 [patch for 2.6.33? 1/1] ata: call flush_dcache_page() around PIO data transfers in libata-aff.c akpm
2010-02-02 22:58 ` James Bottomley
2010-02-02 23:05 ` Andrew Morton
2010-02-02 23:14 ` Jeff Garzik
2010-02-02 23:21 ` James Bottomley
2010-02-02 23:21 ` David Miller
2010-02-02 23:30 ` Alan Cox
2010-02-02 23:32 ` James Bottomley
2010-02-02 23:39 ` David Miller
2010-02-03 10:18 ` Catalin Marinas
2010-02-03 16:40 ` James Bottomley
2010-02-03 17:00 ` Jeff Garzik
2010-02-03 17:06 ` Andrew Morton
2010-02-03 17:15 ` Jeff Garzik
2010-02-03 17:20 ` Andrew Morton
2010-02-03 17:29 ` Jeff Garzik
2010-02-03 17:39 ` James Bottomley
2010-02-04 14:33 ` Catalin Marinas
2010-02-04 15:01 ` James Bottomley
2010-02-04 15:39 ` Catalin Marinas
2010-02-04 21:36 ` James Bottomley
2010-02-03 17:40 ` Alan Cox
2010-02-03 17:46 ` Alan Cox
2010-02-03 17:52 ` Jeff Garzik
2010-02-03 18:00 ` Alan Cox
2010-02-03 18:12 ` Jeff Garzik [this message]
2010-02-03 17:49 ` Catalin Marinas
2010-02-03 17:54 ` Jeff Garzik
2010-02-03 17:09 ` David Miller
2010-02-02 23:14 ` James Bottomley
2010-02-03 10:07 ` Catalin Marinas
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=4B69BC77.4040907@pobox.com \
--to=jgarzik@pobox.com \
--cc=James.Bottomley@suse.de \
--cc=akpm@linux-foundation.org \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=catalin.marinas@arm.com \
--cc=davem@davemloft.net \
--cc=jeff@garzik.org \
--cc=linux-ide@vger.kernel.org \
--cc=stable@kernel.org \
--cc=tj@kernel.org \
/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