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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 AADFCC433DB for ; Wed, 6 Jan 2021 01:30:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 73F9D22D01 for ; Wed, 6 Jan 2021 01:30:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725813AbhAFBa1 (ORCPT ); Tue, 5 Jan 2021 20:30:27 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:58994 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725766AbhAFBa0 (ORCPT ); Tue, 5 Jan 2021 20:30:26 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1609896540; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=IPjM48LYwo/2lrxz087iNT8OSJza9ZbVDyEFZXhhW78=; b=WfKu4m8cI/+7yvwJngR3G2eoOHZ8+RdFoQkQFYnrnD8etcbB5xwDZIvWliQekATrW8Sl6E 9wYyXoLgPRNghbbtgyxT9tUzxlO1uWE3OMqTkkNgqHZliw9UEILtaQTaYcMXZpSwdN3A6b XhLEuCU7FHxp1zM1FMDX8Vik22LTuw8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-593-_hy-AiM8OM2TKx69BohpIA-1; Tue, 05 Jan 2021 20:28:56 -0500 X-MC-Unique: _hy-AiM8OM2TKx69BohpIA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5F5B41842141; Wed, 6 Jan 2021 01:28:55 +0000 (UTC) Received: from T590 (ovpn-12-253.pek2.redhat.com [10.72.12.253]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 28ED17092E; Wed, 6 Jan 2021 01:28:44 +0000 (UTC) Date: Wed, 6 Jan 2021 09:28:39 +0800 From: Ming Lei To: John Garry Cc: Jens Axboe , linux-block@vger.kernel.org, Kashyap Desai Subject: Re: [PATCH] blk-mq: test QUEUE_FLAG_HCTX_ACTIVE for sbitmap_shared in hctx_may_queue Message-ID: <20210106012839.GA3821988@T590> References: <20201227113458.3289082-1-ming.lei@redhat.com> <20210105022017.GA3594357@T590> <20210105111850.GB3619109@T590> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Jan 05, 2021 at 11:38:48AM +0000, John Garry wrote: > On 05/01/2021 11:18, Ming Lei wrote: > > > > > ot set normally.. > > > > It always return true, and might just take a bit more CPU especially the tag queue > > > > depth of magsas_raid and hisi_sas_v3 is quite high. > > > Hi Ming, > > > > > > Right, but we actually tested by hacking the host tag queue depth to be > > > lower such that we should have tag contention, here is an extract from the > > > original series cover letter for my results: > > > > > > Tag depth 4000 (default) 260** > > > > > > Baseline (v5.9-rc1): > > > none sched: 2094K IOPS 513K > > > mq-deadline sched: 2145K IOPS 1336K > > > > > > Final, host_tagset=0 in LLDD *, ***: > > > none sched: 2120K IOPS 550K > > > mq-deadline sched: 2121K IOPS 1309K > > > > > > Final ***: > > > none sched: 2132K IOPS 1185 > > > mq-deadline sched: 2145K IOPS 2097 > > > > > > Maybe my test did not expose the issue. Kashyap also tested this and > > > reported the original issue such that we needed this feature, so I'm > > > confused. > > Hi Ming, > > > 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. -- Ming