From patchwork Wed Jul 14 09:45:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 12376415 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30FB4C11F68 for ; Wed, 14 Jul 2021 09:37:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 116AB6120A for ; Wed, 14 Jul 2021 09:37:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238840AbhGNJkO (ORCPT ); Wed, 14 Jul 2021 05:40:14 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:11414 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238866AbhGNJkJ (ORCPT ); Wed, 14 Jul 2021 05:40:09 -0400 Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4GPslC2yGkzcdKD; Wed, 14 Jul 2021 17:33:59 +0800 (CST) Received: from dggema762-chm.china.huawei.com (10.1.198.204) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Wed, 14 Jul 2021 17:37:16 +0800 Received: from huawei.com (10.175.127.227) by dggema762-chm.china.huawei.com (10.1.198.204) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Wed, 14 Jul 2021 17:37:16 +0800 From: Yu Kuai To: , CC: , , , Subject: [PATCH 3/3] block, bfq: consider request size in bfq_asymmetric_scenario() Date: Wed, 14 Jul 2021 17:45:29 +0800 Message-ID: <20210714094529.758808-4-yukuai3@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210714094529.758808-1-yukuai3@huawei.com> References: <20210714094529.758808-1-yukuai3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggema762-chm.china.huawei.com (10.1.198.204) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org There is a special case when bfq do not need to idle when more than one groups is active: 1) all active queues have the same weight, 2) all active queues have the same request size. 3) all active queues belong to the same I/O-priority class, Each time a request is dispatched, bfq can switch in service queue safely, since the throughput of each active queue is guaranteed to be equivalent. Test procedure: run "fio -numjobs=1 -ioengine=psync -bs=4k -direct=1 -rw=randread..." in different cgroup(not root). Test result: total bandwidth(Mib/s) | total jobs | before this patch | after this patch | | ---------- | ----------------- | --------------------- | | 1 | 33.8 | 33.8 | | 2 | 33.8 | 65.4 (32.7 each job) | | 4 | 33.8 | 106.8 (26.7 each job) | | 8 | 33.8 | 126.4 (15.8 each job) | Signed-off-by: Yu Kuai --- block/bfq-iosched.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index e5a1093ec30a..b78fe8a1537e 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -268,6 +268,15 @@ static struct kmem_cache *bfq_pool; */ #define BFQ_RATE_SHIFT 16 +/* + * 1) bfq keep dispatching requests with same size for at least one second. + * 2) bfq dispatch at lease 1024 requests + * + * We think bfq are dispatching request with same size if the above two + * conditions hold true. + */ +#define VARIED_REQUEST_SIZE(bfqd) ((bfqd)->dispatch_count < 1024 ||\ + time_before(jiffies, (bfqd)->dispatch_time + HZ)) /* * When configured for computing the duration of the weight-raising * for interactive queues automatically (see the comments at the @@ -724,7 +733,8 @@ static bool bfq_asymmetric_scenario(struct bfq_data *bfqd, bool multiple_classes_busy; #ifdef CONFIG_BFQ_GROUP_IOSCHED - if (bfqd->num_groups_with_pending_reqs > 1) + if (bfqd->num_groups_with_pending_reqs > 1 && + VARIED_REQUEST_SIZE(bfqd)) return true; #endif