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 68526C433EF for ; Sat, 21 May 2022 07:23:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240838AbiEUHXL (ORCPT ); Sat, 21 May 2022 03:23:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354750AbiEUHWz (ORCPT ); Sat, 21 May 2022 03:22:55 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8E5D16644A; Sat, 21 May 2022 00:22:37 -0700 (PDT) Received: from kwepemi100018.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4L4w4Q3gCSzgY9W; Sat, 21 May 2022 15:21:10 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by kwepemi100018.china.huawei.com (7.221.188.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 21 May 2022 15:22:35 +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, 21 May 2022 15:22:35 +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> <61b67d5e-829c-8130-7bda-81615d654829@huawei.com> Message-ID: <81411289-e13c-20f5-df63-c059babca57a@huawei.com> Date: Sat, 21 May 2022 15:22:34 +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: <61b67d5e-829c-8130-7bda-81615d654829@huawei.com> 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-block@vger.kernel.org 在 2022/05/14 17:29, yukuai (C) 写道: > 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 ... 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(-) >>>