From: Jens Axboe <axboe@suse.de>
To: Jeff Sipek <jeffpc@optonline.net>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
kernel@kolivas.org, nickpiggin@yahoo.com.au
Subject: Re: IO Priorities
Date: Mon, 13 Dec 2004 17:46:25 +0100 [thread overview]
Message-ID: <20041213164625.GX3033@suse.de> (raw)
In-Reply-To: <20041213164325.GA26031@optonline.net>
On Mon, Dec 13 2004, Jeff Sipek wrote:
> On Mon, Dec 13, 2004 at 03:38:10PM +0100, Jens Axboe wrote:
> > On Mon, Dec 13 2004, Jeff Sipek wrote:
> > > Hello all,
> > > About a week ago, I said I would try to implement IO priorities.
> > > I tried. I got the whole thing done, but there is one major problem - it
> >
> > I did too, did you see my patch?
>
> I did after I sent mine. I was reading it and I noticed:
>
> "Disable TCQ in the hardware/driver by default. Can be changed (as
> always) with the max_depth setting. If you do that, don't expect
> fairness or priorities to work as well."
>
> Would this cause my problem?
Only if you test on SCSI with TCQ enabled. But I already outlined what
your problems are even if you did.
> > Additionally, you don't do anything with the priorities internally.
>
> Sure I do, I multiply the slice by cfq_prio_scale[ioprio]. It did seem
> too simple. :-) Looking at your code right now, I kind of see some code
> that should have been in my implementation as well. Back to coding...
> :-)
If you would base changes on what I already did with CFQ, that would be
handy. You need the CFQ bits anyways.
Updated patch here:
http://www.kernel.org/pub/linux/kernel/people/axboe/patches/v2.6/2.6.10-rc3-mm1/cfq-time-slices-11-2.6.10-rc3-mm1.gz
--
Jens Axboe
prev parent reply other threads:[~2004-12-13 16:47 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-13 14:22 IO Priorities Jeff Sipek
2004-12-13 14:38 ` Jens Axboe
2004-12-13 16:43 ` Jeff Sipek
2004-12-13 16:46 ` Jens Axboe [this message]
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