From: Mike Anderson <andmike@us.ibm.com>
To: "Jeff V. Merkey" <jmerkey@vger.timpanogas.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: queue_nr_requests needs to be selective
Date: Fri, 1 Mar 2002 16:51:04 -0800 [thread overview]
Message-ID: <20020301165104.C6778@beaverton.ibm.com> (raw)
In-Reply-To: <20020301132254.A11528@vger.timpanogas.org>
In-Reply-To: <20020301132254.A11528@vger.timpanogas.org>; from jmerkey@vger.timpanogas.org on Fri, Mar 01, 2002 at 01:22:54PM -0700
Jeff V. Merkey [jmerkey@vger.timpanogas.org] wrote:
>
> ..snip..
>
> What is really needed here is to allow queue_nr_requests to be
> configurable on a per adapter/device basis for these high end
> raid cards like 3Ware since in a RAID 0 configuration, 8 drives
> are in essence a terabyte (1.3 terrabytes in our configuration)
> and each adapter is showing up as a 1.3 TB device. 64/128
> requests are simply not enough to get the full spectrum of
> performance atainable with these cards.
>
Not having direct experience on this card it appears that increasing the
queue_nr_requests number will not allow you to have more ios in flight.
Unless I am reading the driver wrong you will be limited to
TW_MAX_CMDS_PER_LUN (15). This value is used by scsi_build_commandblocks
to allocate scsi commands for your scsi_device. This driver does not provide
a select_queue_depths function which allows for increase to the default
template value.
Could it be that the experimentation of increasing this number has
allowed for better merging.
-Mike
--
Michael Anderson
andmike@us.ibm.com
next prev parent reply other threads:[~2002-03-02 2:45 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-01 20:22 queue_nr_requests needs to be selective Jeff V. Merkey
2002-03-01 20:43 ` Andrew Morton
2002-03-01 21:03 ` Alan Cox
2002-03-01 23:22 ` Jeff V. Merkey
2002-03-01 23:20 ` Jeff V. Merkey
2002-03-01 23:23 ` Andrew Morton
2002-03-02 0:27 ` Jeff V. Merkey
2002-03-02 0:49 ` Andrew Morton
2002-03-02 2:16 ` Jeff V. Merkey
2002-03-02 3:50 ` Andrew Morton
2002-03-02 4:34 ` Jeff V. Merkey
2002-03-02 7:33 ` Jeff V. Merkey
2002-03-02 9:10 ` Jens Axboe
2002-03-02 9:22 ` Andrew Morton
2002-03-04 9:09 ` Jens Axboe
2002-03-02 0:51 ` Mike Anderson [this message]
2002-03-02 4:39 ` Jeff V. Merkey
2002-03-02 5:59 ` Jeff V. Merkey
2002-03-02 6:01 ` Jeff V. Merkey
2002-03-02 6:16 ` Jeff V. Merkey
2002-03-04 7:16 ` Mike Anderson
2002-03-04 17:39 ` Jeff V. Merkey
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=20020301165104.C6778@beaverton.ibm.com \
--to=andmike@us.ibm.com \
--cc=jmerkey@vger.timpanogas.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox