From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1072BC433FE for ; Sun, 24 Apr 2022 02:44:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237736AbiDXCrh (ORCPT ); Sat, 23 Apr 2022 22:47:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56624 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237754AbiDXCrb (ORCPT ); Sat, 23 Apr 2022 22:47:31 -0400 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A61FD11D230; Sat, 23 Apr 2022 19:44:31 -0700 (PDT) Received: from kwepemi500017.china.huawei.com (unknown [172.30.72.57]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4KmCBh2JbXz1JBGZ; Sun, 24 Apr 2022 10:43:40 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by kwepemi500017.china.huawei.com (7.221.188.110) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sun, 24 Apr 2022 10:44:29 +0800 Received: from [10.174.176.73] (10.174.176.73) by kwepemm600009.china.huawei.com (7.193.23.164) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sun, 24 Apr 2022 10:44:29 +0800 Subject: Re: [PATCH -next v2 0/5] support concurrent sync io for bfq on a specail occasion To: , , , CC: , , , References: <20220416093753.3054696-1-yukuai3@huawei.com> From: "yukuai (C)" Message-ID: Date: Sun, 24 Apr 2022 10:44:28 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20220416093753.3054696-1-yukuai3@huawei.com> Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.176.73] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemm600009.china.huawei.com (7.193.23.164) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org friendly ping ... ÔÚ 2022/04/16 17:37, Yu Kuai дµÀ: > Changes in v2: > - Use a different aporch to count root group, which is much simple. > > Currently, bfq can't handle sync io concurrently as long as they > are not issued from root group. This is because > 'bfqd->num_groups_with_pending_reqs > 0' is always true in > bfq_asymmetric_scenario(). > > The way that bfqg is counted to 'num_groups_with_pending_reqs': > > Before this patchset: > 1) root group will never be counted. > 2) Count if bfqg or it's child bfqgs have pending requests. > 3) Don't count if bfqg and it's child bfqgs complete all the requests. > > After this patchset: > 1) root group is counted. > 2) Count if bfqg have pending requests. > This is because, for example: > if sync ios are issued from cgroup /root/c1/c2, root, c1 and c2 will all > be counted into 'num_groups_with_pending_reqs', which makes it impossible > to handle sync ios concurrently. > > 3) Don't count if bfqg complete all the requests. > This is because, for example: > t1 issue sync io on root group, t2 and t3 issue sync io on the same child > group. num_groups_with_pending_reqs is 2 now. After t1 stopped, > num_groups_with_pending_reqs is still 2. sync io from t2 and t3 still can't > be handled concurrently. > > fio test script: startdelay is used to avoid queue merging > [global] > filename=/dev/nvme0n1 > allow_mounted_write=0 > ioengine=psync > direct=1 > ioscheduler=bfq > offset_increment=10g > group_reporting > rw=randwrite > bs=4k > > [test1] > numjobs=1 > > [test2] > startdelay=1 > numjobs=1 > > [test3] > startdelay=2 > numjobs=1 > > [test4] > startdelay=3 > numjobs=1 > > [test5] > startdelay=4 > numjobs=1 > > [test6] > startdelay=5 > numjobs=1 > > [test7] > startdelay=6 > numjobs=1 > > [test8] > startdelay=7 > numjobs=1 > > test result: > running fio on root cgroup > v5.18-rc1: 550 Mib/s > v5.18-rc1-patched: 550 Mib/s > > running fio on non-root cgroup > v5.18-rc1: 349 Mib/s > v5.18-rc1-patched: 550 Mib/s > > Yu Kuai (5): > block, bfq: cleanup bfq_weights_tree add/remove apis > block, bfq: add fake weight_counter for weight-raised queue > bfq, block: record how many queues have pending requests in bfq_group > block, bfq: refactor the counting of 'num_groups_with_pending_reqs' > block, bfq: do not idle if only one cgroup is activated > > block/bfq-cgroup.c | 1 + > block/bfq-iosched.c | 90 +++++++++++++++++++-------------------------- > block/bfq-iosched.h | 26 ++++++------- > block/bfq-wf2q.c | 30 +++------------ > 4 files changed, 56 insertions(+), 91 deletions(-) >