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[2620:137:e000::1:18]) by mx.google.com with ESMTPS id k3-20020a654643000000b003c15242c486si13180475pgr.787.2022.05.09.02.49.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 May 2022 02:49:30 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7033F2272C0; Mon, 9 May 2022 02:34:35 -0700 (PDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233759AbiEEBEv (ORCPT + 99 others); Wed, 4 May 2022 21:04:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233780AbiEEBEt (ORCPT ); Wed, 4 May 2022 21:04:49 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 808972317C; Wed, 4 May 2022 18:01:11 -0700 (PDT) Received: from kwepemi100013.china.huawei.com (unknown [172.30.72.57]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4KtwHR47MvzCsWV; Thu, 5 May 2022 08:56:03 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by kwepemi100013.china.huawei.com (7.221.188.136) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 5 May 2022 09:00:44 +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; Thu, 5 May 2022 09:00:43 +0800 Subject: Re: [PATCH -next v5 0/3] support concurrent sync io for bfq on a specail occasion To: , CC: , , , , , References: <20220428120837.3737765-1-yukuai3@huawei.com> From: "yukuai (C)" Message-ID: Date: Thu, 5 May 2022 09:00:42 +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: <20220428120837.3737765-1-yukuai3@huawei.com> Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.176.73] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemm600009.china.huawei.com (7.193.23.164) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-3.0 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, RDNS_NONE,SPF_HELO_NONE,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Paolo Can you take a look at this patchset? It has been quite a long time since we spotted this problem... Thanks, Kuai ?? 2022/04/28 20:08, Yu Kuai ะด??: > Changes in v5: > - rename bfq_add_busy_queues() to bfq_inc_busy_queues() in patch 1 > - fix wrong definition in patch 1 > - fix spelling mistake in patch 2: leaset -> least > - update comments in patch 3 > - add reviewed-by tag in patch 2,3 > > Changes in v4: > - split bfq_update_busy_queues() to bfq_add/dec_busy_queues(), > suggested by Jan Kara. > - remove unused 'in_groups_with_pending_reqs', > > Changes in v3: > - remove the cleanup patch that is irrelevant now(I'll post it > separately). > - instead of hacking wr queues and using weights tree insertion/removal, > using bfq_add/del_bfqq_busy() to count the number of groups > (suggested by Jan Kara). > > Changes in v2: > - Use a different approch 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 into '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 at least one bfqq that is marked busy. > 3) Don't count if bfqg doesn't have any busy bfqqs. > > The main reason to use busy state of bfqq instead of 'pending requests' > is that bfqq can stay busy after dispatching the last request if idling > is needed for service guarantees. > > With the above changes, concurrent sync io can be supported if only > one group is activated. > > 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 > > Note that I also test null_blk with "irqmode=2 > completion_nsec=100000000(100ms) hw_queue_depth=1", and tests show > that service guarantees are still preserved. > > Previous versions: > RFC: https://lore.kernel.org/all/20211127101132.486806-1-yukuai3@huawei.com/ > v1: https://lore.kernel.org/all/20220305091205.4188398-1-yukuai3@huawei.com/ > v2: https://lore.kernel.org/all/20220416093753.3054696-1-yukuai3@huawei.com/ > v3: https://lore.kernel.org/all/20220427124722.48465-1-yukuai3@huawei.com/ > v4: https://lore.kernel.org/all/20220428111907.3635820-1-yukuai3@huawei.com/ > > Yu Kuai (3): > block, bfq: record how many queues are busy in bfq_group > block, bfq: refactor the counting of 'num_groups_with_pending_reqs' > block, bfq: do not idle if only one group is activated > > block/bfq-cgroup.c | 1 + > block/bfq-iosched.c | 48 +++----------------------------------- > block/bfq-iosched.h | 57 +++++++-------------------------------------- > block/bfq-wf2q.c | 35 +++++++++++++++++----------- > 4 files changed, 35 insertions(+), 106 deletions(-) >