Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755399Ab1BROyn (ORCPT ); Fri, 18 Feb 2011 09:54:43 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48847 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752417Ab1BROyl (ORCPT ); Fri, 18 Feb 2011 09:54:41 -0500 Date: Fri, 18 Feb 2011 09:54:32 -0500 From: Vivek Goyal To: Gui Jianfeng Cc: Jens Axboe , Shaohua Li , lkml , Chad Talbott , Divyesh Shah Subject: Re: [PATCH 3/6 v4] cfq-iosched: Introduce vdisktime and io weight for CFQ queue Message-ID: <20110218145432.GA26654@redhat.com> References: <4D51ED26.8050809@cn.fujitsu.com> <4D539804.9090308@cn.fujitsu.com> <20110214181322.GJ13097@redhat.com> <4D5E0BE2.6020104@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D5E0BE2.6020104@cn.fujitsu.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3072 Lines: 76 On Fri, Feb 18, 2011 at 02:04:18PM +0800, Gui Jianfeng wrote: > Vivek Goyal wrote: > > On Thu, Feb 10, 2011 at 03:47:16PM +0800, Gui Jianfeng wrote: > > > > [..] > >> +/* > >> + * The time when a CFQ queue is put onto a service tree is recoreded in > >> + * cfqq->reposition_time. Currently, we check the first priority CFQ queues > >> + * on each service tree, and select the workload type that contains the lowest > >> + * reposition_time CFQ queue among them. > >> + */ > >> static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, > >> struct cfq_group *cfqg, enum wl_prio_t prio) > >> { > >> struct cfq_entity *cfqe; > >> + struct cfq_queue *cfqq; > >> + unsigned long lowest_start_time; > >> int i; > >> - bool key_valid = false; > >> - unsigned long lowest_key = 0; > >> + bool time_valid = false; > >> enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; > >> > >> + /* > >> + * TODO: We may take io priority and io class into account when > >> + * choosing a workload type. But for the time being just make use of > >> + * reposition_time only. > >> + */ > >> for (i = 0; i <= SYNC_WORKLOAD; ++i) { > >> - /* select the one with lowest rb_key */ > >> cfqe = cfq_rb_first(service_tree_for(cfqg, prio, i)); > >> - if (cfqe && > >> - (!key_valid || time_before(cfqe->rb_key, lowest_key))) { > >> - lowest_key = cfqe->rb_key; > >> + cfqq = cfqq_of_entity(cfqe); > >> + if (cfqe && (!time_valid || > >> + time_before(cfqq->reposition_time, > >> + lowest_start_time))) { > >> + lowest_start_time = cfqq->reposition_time; > > > > Gui, > > > > Have you had a chance to run some mixed workloads in a group (some sync, > > some async and some sync-idle queues), and see how latency and throughput > > of sync-idle workload changes due to this "resposition_time" logic. I > > just want to make sure that latency of sync-noidle workload does not > > go up as that's the workload that people care and gets noticed first. > > Hi Vivek, > > I made a quick test by using fio. It seems the number changes little > between vanilla kernel and patched kernel. > > > Vanilla: SYNC read SYNC-NOIDLE read ASYNC write > 1. 23,640KB/s 5.40 ---- 6,696KB/s 19.07 ---- 50,142KB/s 128.00 > 2. 24,459KB/s 5.22 ---- 6,775KB/s 18.86 ---- 47,349KB/s 129.89 > 3. 25,929KB/s 4.93 ---- 7,378KB/s 17.32 ---- 32,350KB/s 131.88 > > Patched: SYNC read SYNC-NOIDLE read ASYNC write > 1. 24,000KB/s 5.32 ---- 6,942KB/s 18.39 ---- 30,860KB/s 135.95 > 2. 23,678KB/s 5.40 ---- 7,274KB/s 17.58 ---- 67,432KB/s 120.44 > 3. 23,004KB/s 5.55 ---- 6,621KB/s 19.30 ---- 36,536KB/s 148.64 Hi Gui, Do you also have latency numbers? I am especially interested max completion latencies of SYNC-NOIDLE workload. Thanks Vivek -- 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/