Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755117AbZJDLed (ORCPT ); Sun, 4 Oct 2009 07:34:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753613AbZJDLed (ORCPT ); Sun, 4 Oct 2009 07:34:33 -0400 Received: from mail.gmx.net ([213.165.64.20]:35805 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753257AbZJDLec (ORCPT ); Sun, 4 Oct 2009 07:34:32 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX192qpQ21wB2Pksvr3yhs3TuBt1VrpUpjw62ARxcWN cvnWnaRgGNJKjq Subject: Re: Do not overload dispatch queue (Was: Re: IO scheduler based IO controller V10) From: Mike Galbraith To: Jens Axboe Cc: Vivek Goyal , Ingo Molnar , Linus Torvalds , Ulrich Lukas , linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, dm-devel@redhat.com, nauman@google.com, dpshah@google.com, lizf@cn.fujitsu.com, mikew@google.com, fchecconi@gmail.com, paolo.valente@unimore.it, ryov@valinux.co.jp, fernando@oss.ntt.co.jp, jmoyer@redhat.com, dhaval@linux.vnet.ibm.com, balbir@linux.vnet.ibm.com, righi.andrea@gmail.com, m-ikeda@ds.jp.nec.com, agk@redhat.com, akpm@linux-foundation.org, peterz@infradead.org, jmarchan@redhat.com, riel@redhat.com In-Reply-To: <1254653434.7237.18.camel@marge.simson.net> References: <20091003124049.GB12925@redhat.com> <20091003132115.GB31616@kernel.dk> <20091003135623.GD12925@redhat.com> <1254578553.7499.5.camel@marge.simson.net> <20091003142840.GE31616@kernel.dk> <1254581496.8293.8.camel@marge.simson.net> <20091003151445.GF31616@kernel.dk> <1254585420.7539.2.camel@marge.simson.net> <20091003173532.GG31616@kernel.dk> <1254596864.7153.9.camel@marge.simson.net> <20091003192321.GA26573@kernel.dk> <1254599386.7153.46.camel@marge.simson.net> <1254653434.7237.18.camel@marge.simson.net> Content-Type: text/plain Date: Sun, 04 Oct 2009 13:33:33 +0200 Message-Id: <1254656013.7098.2.camel@marge.simson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1.1 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 X-FuHaFi: 0.5600000000000001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1433 Lines: 45 Wrong one. Let's try the post java version instead. 8e29675: "implement slower async initiate and queue ramp up" introduced a throughput regression for concurrent reader vs writer. Adjusting async delay to use cfq_slice_async restored throughput. Signed-off-by: Mike Galbraith --- block/cfq-iosched.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) Index: linux-2.6/block/cfq-iosched.c =================================================================== --- linux-2.6.orig/block/cfq-iosched.c +++ linux-2.6/block/cfq-iosched.c @@ -1343,17 +1343,18 @@ static int cfq_dispatch_requests(struct */ if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_desktop) { unsigned long last_sync = jiffies - cfqd->last_end_sync_rq; + unsigned long slice = cfq_slice_async; unsigned int depth; /* * must wait a bit longer */ - if (last_sync < cfq_slice_sync) { - cfq_schedule_dispatch(cfqd, cfq_slice_sync - last_sync); + if (last_sync < slice) { + cfq_schedule_dispatch(cfqd, slice - last_sync); return 0; } - depth = last_sync / cfq_slice_sync; + depth = last_sync / slice; if (depth < max_dispatch) max_dispatch = depth; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/