From: Jeff Garzik <jeff@garzik.org>
To: Kevin Radloff <radsaq@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, linux-kernel@vger.kernel.org
Subject: Re: PATCH: Fix broken PIO with libata
Date: Tue, 16 May 2006 13:27:08 -0400 [thread overview]
Message-ID: <446A0B6C.8050901@garzik.org> (raw)
In-Reply-To: <3b0ffc1f0605161019j7149f72bv309db19eb9d12dd8@mail.gmail.com>
Kevin Radloff wrote:
> On 5/16/06, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>> On Maw, 2006-05-16 at 11:33 -0400, Kevin Radloff wrote:
>> > However, I still have a problem with pata_pcmcia (that I actually
>> > experienced also with the ide-cs driver) where sustained reading or
>> > writing to the CF card spikes the CPU with nearly 100% system time.
>>
>> That is normal. The PCMCIA devices don't support DMA. As a result of
>> this the processor has to fetch each byte itself over the ISA speed
>> PCMCIA bus link.
>
> Hrm, as I recall that only started happening with ide-cs sometime in
> the single digits of 2.6.x.. And note that it's only maxing out at
> about 1.5MB/s. Should that saturate my laptop's 1.1GHz Pentium M
> processor?
Doing data xfer using PIO rather than DMA definitely eats tons of CPU
cycles.
Jeff
next prev parent reply other threads:[~2006-05-16 17:27 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-16 14:39 Alan Cox
2006-05-16 15:33 ` Kevin Radloff
2006-05-16 15:53 ` Alan Cox
2006-05-16 17:19 ` Kevin Radloff
2006-05-16 17:27 ` Jeff Garzik [this message]
2006-05-16 17:39 ` Tejun Heo
2006-05-16 18:13 ` Kevin Radloff
2006-05-16 22:51 ` Alan Cox
2006-05-16 15:36 ` Tejun Heo
2006-05-16 15:48 ` Jeff Garzik
2006-05-16 15:57 ` Tejun Heo
2006-05-16 23:00 ` Paul Mackerras
2006-05-16 17:10 ` Jeff Garzik
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=446A0B6C.8050901@garzik.org \
--to=jeff@garzik.org \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=linux-kernel@vger.kernel.org \
--cc=radsaq@gmail.com \
/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
all inboxes | Powered by JetHome®