From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamie Lokier Subject: Re: [PATCH] speed up SATA Date: Mon, 29 Mar 2004 13:50:03 +0100 Sender: linux-ide-owner@vger.kernel.org Message-ID: <20040329125003.GD4984@mail.shareable.org> References: <40670BD9.9020707@pobox.com> <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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail.shareable.org ([81.29.64.88]:25235 "EHLO mail.shareable.org") by vger.kernel.org with ESMTP id S262941AbUC2MuL (ORCPT ); Mon, 29 Mar 2004 07:50:11 -0500 Content-Disposition: inline In-Reply-To: <20040329124421.GB24370@suse.de> List-Id: linux-ide@vger.kernel.org To: Jens Axboe Cc: Jeff Garzik , Nick Piggin , linux-ide@vger.kernel.org, Linux Kernel , Andrew Morton Jens Axboe wrote: > > 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...) Then there's another question: when deciding whether you can issue another TCQ-read, do you compare the number of outstanding TCQ-reads against the TCQ-read limit, or compare the _total_ number of outstanding TCQs against the TCQ-read limit? Similarly for writes. There are several other logical combinations that could be used. Each condition will have a different effect on mean and peak latencies under different load patterns. I'm not sure which makes more sense, or even if multiple conditions should be used together. -- Jamie