Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752802Ab1BRGEi (ORCPT ); Fri, 18 Feb 2011 01:04:38 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:63914 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751529Ab1BRGEg (ORCPT ); Fri, 18 Feb 2011 01:04:36 -0500 Message-ID: <4D5E0BE2.6020104@cn.fujitsu.com> Date: Fri, 18 Feb 2011 14:04:18 +0800 From: Gui Jianfeng User-Agent: Thunderbird 2.0.0.24 (Windows/20100228) MIME-Version: 1.0 To: Vivek Goyal 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 References: <4D51ED26.8050809@cn.fujitsu.com> <4D539804.9090308@cn.fujitsu.com> <20110214181322.GJ13097@redhat.com> In-Reply-To: <20110214181322.GJ13097@redhat.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-02-18 14:03:29, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-02-18 14:03:30, Serialize complete at 2011-02-18 14:03:30 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2764 Lines: 70 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 Thanks, Gui -- 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/