From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH] speed up SATA Date: Mon, 29 Mar 2004 15:08:50 +0200 Sender: linux-kernel-owner@vger.kernel.org Message-ID: <20040329130850.GD24370@suse.de> References: <20040328173508.GI24370@suse.de> <40670FDB.6080409@pobox.com> <20040328175436.GL24370@suse.de> <20040328180809.GB1087@mail.shareable.org> <20040328181502.GO24370@suse.de> <40671FAF.6080501@pobox.com> <20040329080943.GR24370@suse.de> <20040329124147.GC4984@mail.shareable.org> <20040329124421.GB24370@suse.de> <1080565536.3570.4.camel@laptop.fenrus.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1080565536.3570.4.camel@laptop.fenrus.com> To: Arjan van de Ven Cc: Jamie Lokier , Jeff Garzik , Nick Piggin , linux-ide@vger.kernel.org, Linux Kernel , Andrew Morton List-Id: linux-ide@vger.kernel.org On Mon, Mar 29 2004, Arjan van de Ven wrote: > On Mon, 2004-03-29 at 14:44, Jens Axboe wrote: > > On Mon, Mar 29 2004, Jamie Lokier wrote: > > > Jens Axboe wrote: > > > > Could be used to limit tcq depth, not just request sizes solving two > > > > problems at once. I already have a tiny bit of keeping this > > > > accounting to do proper unplugs (right now it just looks at missing > > > > requests from the pool, doesn't work on tcq). > > > > > > Does it make sense to allow different numbers of outstanding TCQ-reads > > > and TCQ-writes? > > > > Might not be a silly thing to experiment with, definitely something that > > should be tested (added to list...) > > I wonder if the max read size could/should be correlated with the > readahead size for such devices... it sounds like a related property at > least. Indeed, it would be best to keep the read-ahead window at least a multiple of the max read size. So you don't get the nasty effects of having a 128k read-ahead window, but device with 255 sector limit resulting in 124KB + 4KB read. -- Jens Axboe