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 9D563C433F5 for ; Sat, 14 May 2022 09:29:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231290AbiENJ3Q (ORCPT ); Sat, 14 May 2022 05:29:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231211AbiENJ3O (ORCPT ); Sat, 14 May 2022 05:29:14 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04DCEBC0B; Sat, 14 May 2022 02:29:12 -0700 (PDT) Received: from kwepemi100019.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4L0gB41FW6zGpZj; Sat, 14 May 2022 17:26:20 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by kwepemi100019.china.huawei.com (7.221.188.189) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 14 May 2022 17:29:11 +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; Sat, 14 May 2022 17:29:10 +0800 Subject: Re: [PATCH -next v5 0/3] support concurrent sync io for bfq on a specail occasion From: "yukuai (C)" To: , CC: , , , , , References: <20220428120837.3737765-1-yukuai3@huawei.com> Message-ID: <61b67d5e-829c-8130-7bda-81615d654829@huawei.com> Date: Sat, 14 May 2022 17:29:09 +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: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.176.73] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) 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 在 2022/05/05 9:00, yukuai (C) 写道: > Hi, Paolo > > Can you take a look at this patchset? It has been quite a long time > since we spotted this problem... > friendly ping ... > Thanks, > Kuai > > 在 2022/04/28 20:08, Yu Kuai 写道: >> 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(-) >>