From: "Jeff V. Merkey" <jmerkey@vger.timpanogas.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Andrew Morton <akpm@zip.com.au>, linux-kernel@vger.kernel.org
Subject: Re: queue_nr_requests needs to be selective
Date: Fri, 1 Mar 2002 16:22:02 -0700 [thread overview]
Message-ID: <20020301162202.B12413@vger.timpanogas.org> (raw)
In-Reply-To: <3C7FE7DD.98121E87@zip.com.au> <E16guBW-00051l-00@the-village.bc.nu>
In-Reply-To: <E16guBW-00051l-00@the-village.bc.nu>; from alan@lxorguk.ukuu.org.uk on Fri, Mar 01, 2002 at 09:03:22PM +0000
On Fri, Mar 01, 2002 at 09:03:22PM +0000, Alan Cox wrote:
> > I don't immediately see why increasing the queue length should
> > increase bandwidth in this manner. One possibility is that
>
> Latency on the controllers ? With caches on the controller and disks you
> can have a lot of requests actually in flight
Since 3ware uses a switched architecture, there are a lot of requests
in flight. Can we get the default value increased or alternately, allow
RAID drivers to submit a local queue_nr_request value per adapter
so for those cards with 8 drives that make themselves look like
a single drive to Linux, sufficient buffers are available to prevent
threads feeding the device from going to sleep all the time?
:-)
Jeff
next prev parent reply other threads:[~2002-03-01 23:08 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-01 20:22 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 [this message]
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
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
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