From: Jeff Garzik <jeff@garzik.org>
To: Mark Lord <liml@rtr.ca>
Cc: Daniel J Blueman <daniel.blueman@gmail.com>,
bzolnier@gmail.com, linux-ide@vger.kernel.org,
Linux Kernel <linux-kernel@vger.kernel.org>,
Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: Compact Flash performance...
Date: Thu, 31 May 2007 19:26:51 -0400 [thread overview]
Message-ID: <465F59BB.9040909@garzik.org> (raw)
In-Reply-To: <465F4ED0.10508@rtr.ca>
Mark Lord wrote:
> To maximize throughput, some kind of host-queuing would be needed,
> or just have the driver sit in a tight loop, starting the next I/O
> immediately when the previous one finishes. Linux isn't that quick (yet).
I was talking on IRC with Tejun just recently. There are several
controllers (and/or "situations") like this, where some amount of host
queueing would permit greater throughput, even when NCQ is not
supported. sata_sx4 is the most dramatic example, where host queueing
could potentially increase speed by a factor of 10 or more, since it is
penalized by an awful two-irq-per-command (w/ a per-host bottleneck to
boot) setup. Silicon Image has a "command buffer". And overall, I
designed ->qc_prep() hook separate from ->qc_issue() to enable the
prepartion of multiple commands such that it only takes a simple "go"
I/O to start a transaction, immediately after the previous one ends.
Jeff
next prev parent reply other threads:[~2007-05-31 23:26 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-30 22:10 Compact Flash performance Daniel J Blueman
2007-05-30 22:31 ` Lee Revell
2007-05-31 9:18 ` Daniel J Blueman
2007-05-30 22:56 ` Bartlomiej Zolnierkiewicz
2007-05-31 3:24 ` Mark Lord
2007-05-31 9:22 ` Daniel J Blueman
2007-05-31 12:22 ` Mark Lord
2007-05-31 17:25 ` Daniel J Blueman
2007-05-31 20:54 ` Mark Lord
2007-05-31 21:39 ` Daniel J Blueman
2007-05-31 22:33 ` Mark Lord
2007-05-31 22:35 ` Mark Lord
2007-05-31 22:37 ` Jeff Garzik
2007-05-31 22:43 ` Mark Lord
2007-06-02 5:10 ` Willy Tarreau
2007-05-31 23:47 ` Daniel J Blueman
2007-05-31 22:40 ` Mark Lord
2007-05-31 23:26 ` Jeff Garzik [this message]
[not found] <fa.XmtWMJk5gwBC00HJh+5O62Vx8eA@ifi.uio.no>
[not found] ` <fa.fl4+oXGwE5VC39h2DLdFoBUbqV4@ifi.uio.no>
[not found] ` <fa.+cW0LouEqSiZ6zrmBDeBJxRjPTg@ifi.uio.no>
[not found] ` <fa.PM7erd/Gm1gq8ZshwTBJwux7o6o@ifi.uio.no>
[not found] ` <fa.MYVClL+Q9g/jFTcUNWOeysiV0Ig@ifi.uio.no>
[not found] ` <fa.Q4zXu+xtMAT5H5vbl/zgxZk/Ivo@ifi.uio.no>
2007-06-01 0:00 ` Robert Hancock
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=465F59BB.9040909@garzik.org \
--to=jeff@garzik.org \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=bzolnier@gmail.com \
--cc=daniel.blueman@gmail.com \
--cc=liml@rtr.ca \
--cc=linux-ide@vger.kernel.org \
--cc=linux-kernel@vger.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.