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 X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 CF4D1C433E0 for ; Wed, 6 Jan 2021 11:40:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 99FAF23104 for ; Wed, 6 Jan 2021 11:40:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726452AbhAFLkH (ORCPT ); Wed, 6 Jan 2021 06:40:07 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:2296 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726258AbhAFLkH (ORCPT ); Wed, 6 Jan 2021 06:40:07 -0500 Received: from fraeml713-chm.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4D9nNy6sn1z67Xxf; Wed, 6 Jan 2021 19:35:46 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml713-chm.china.huawei.com (10.206.15.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Wed, 6 Jan 2021 12:39:25 +0100 Received: from [10.210.170.66] (10.210.170.66) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Wed, 6 Jan 2021 11:39:24 +0000 From: John Garry Subject: Re: [PATCH] blk-mq: test QUEUE_FLAG_HCTX_ACTIVE for sbitmap_shared in hctx_may_queue To: Ming Lei , Kashyap Desai CC: Jens Axboe , References: <20201227113458.3289082-1-ming.lei@redhat.com> <20210105022017.GA3594357@T590> <20210105111850.GB3619109@T590> <20210106012839.GA3821988@T590> Message-ID: <5430c277-92ab-b24d-6479-2e8c16b0c667@huawei.com> Date: Wed, 6 Jan 2021 11:38:22 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <20210106012839.GA3821988@T590> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.210.170.66] X-ClientProxiedBy: lhreml718-chm.china.huawei.com (10.201.108.69) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 06/01/2021 01:28, Ming Lei wrote: >>> How many LUNs are involved in above test with 260 depth? >> For me, there was 12 SAS SSDs; for convenience here is the cover letter with >> details: >> https://lore.kernel.org/linux-block/1597850436-116171-1-git-send-email-john.garry@huawei.com/ >> >> IIRC, for megaraid sas, Kashyap used many more LUNs for testing (64) and >> high fio depth (128) but did not reduce .can_queue, topic originally raised >> here: >> https://lore.kernel.org/linux-block/29f8062c1fccace73c45252073232917@mail.gmail.com/ > OK, in both tests, nr_luns are big enough wrt. 260 depth. Maybe that is > why very low IOPS is observed in 'Final(hosttag=1)' with 260 depth. > > I'd suggest to run your previous test again after applying this patch, > and see if difference can be observed. Hi Ming, I tested and didn't see a noticeable difference with the fix when using the reducing tag queue depth. I got ~500K IOPs with tag queue depth of 260, as opposed to 2M with full tag queue depth. However I was doubtful on this test method before. Regardless, your change and this feature still look proper. @Kashyap, it would be great if you guys could test this also on that same setup you described previously: https://lore.kernel.org/linux-block/29f8062c1fccace73c45252073232917@mail.gmail.com/ Thanks, John