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=-5.3 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 95DD3C11F65 for ; Wed, 30 Jun 2021 18:59:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C55961437 for ; Wed, 30 Jun 2021 18:59:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233580AbhF3TCE (ORCPT ); Wed, 30 Jun 2021 15:02:04 -0400 Received: from mail-pg1-f180.google.com ([209.85.215.180]:43819 "EHLO mail-pg1-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232851AbhF3TCE (ORCPT ); Wed, 30 Jun 2021 15:02:04 -0400 Received: by mail-pg1-f180.google.com with SMTP id o18so2642411pgu.10 for ; Wed, 30 Jun 2021 11:59:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=0Wi/OHievHiEkbKZk39MUJJHz8CqqbZiqlSseobXU1M=; b=IBXGk4PbQ7iQgqb3M93irT2e1jkxNyM7naGh3qhjxxxWlVsVNRKFWb3bivIDSMWKaD 8u1SjCjUMevb5dcXV6I+S/R1XkRdy0lqaEzJc3L3x7SyMz4r419TYG2YM79IawnDQefp UUNJsZezEx65nA5xcTQTZv03zliiWE7fc7ZXCvzJSsHQlPWrdmqvAqK0tI1JuEaW4kO5 2UUZKuGBFK1cwZmhUcCVwH6xe+KYkzT23UTI90mxrcj1QB1vEAO5YwHOjazpjevA+CES SjY8yqPtNeDYllkN45BwcXvEmCZTqJo8suYl60nFjXp345C2bl5c/27irMkAbXdxjRDa 3aSQ== X-Gm-Message-State: AOAM533R0Hkf56C2vRXNjqo7as9JdzJ1GRwcTatlLGS6OGrQ859xhCJj C0+3Vy+xUzIGzb0LOT2vd7A= X-Google-Smtp-Source: ABdhPJy5tD0xCLQMXKqgVzsGUSIoGa7yBsH1MnAew8zlYGkpf2YhN3yoWG+sZC4S96FcwF5kZZ03gw== X-Received: by 2002:a63:b0b:: with SMTP id 11mr35524933pgl.341.1625079575156; Wed, 30 Jun 2021 11:59:35 -0700 (PDT) Received: from ?IPv6:2601:647:4802:9070:8e5:b428:30c3:f97b? ([2601:647:4802:9070:8e5:b428:30c3:f97b]) by smtp.gmail.com with ESMTPSA id c24sm22501230pfd.167.2021.06.30.11.59.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 30 Jun 2021 11:59:34 -0700 (PDT) Subject: Re: [PATCH 0/2] blk-mq: fix blk_mq_alloc_request_hctx To: Ming Lei , Hannes Reinecke Cc: Jens Axboe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Christoph Hellwig , Daniel Wagner , Wen Xiong , John Garry References: <20210629074951.1981284-1-ming.lei@redhat.com> <5f304121-38ce-034b-2d17-93d136c77fe6@suse.de> From: Sagi Grimberg Message-ID: Date: Wed, 30 Jun 2021 11:59:33 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org >>>> Shouldn't we rather modify the tagset to only refer to the current online >>>> CPUs _only_, thereby never submit a connect request for hctx with only >>>> offline CPUs? >>> >>> Then you may setup very less io queues, and performance may suffer even >>> though lots of CPUs become online later. >>> ; >> Only if we stay with the reduced number of I/O queues. Which is not what I'm >> proposing; I'd rather prefer to connect and disconnect queues from the cpu >> hotplug handler. For starters we could even trigger a reset once the first >> cpu within a hctx is onlined. > > Yeah, that need one big/complicated patchset, but not see any advantages > over this simple approach. I tend to agree with Ming here. 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=-5.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 13445C11F65 for ; Wed, 30 Jun 2021 18:59:50 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D8D37613DF for ; Wed, 30 Jun 2021 18:59:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D8D37613DF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=grimberg.me Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:Cc:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=cHAtORczqRXG9gIz3db7OUq21zJnSf80rOTVHAWgHpM=; b=GZtGvVIwVbBMkVfVK4FOR8aFuS tUiZQWImYz8sChUuZiEU03pGJOhYb6URFMkqXZ3APoG+6uttaP2QjGqjaZ6z3qPmFmnZnRBeQHQYh UGzdZkAM7J32qBW+qiWALc9nsoxVB7x07ml7rSC9AZSVg6YzGoUTvEYAd2GLnxSTh2Um4pUaCM3hd 4EiQiB/Ehlta+xN5165qQaZy1zM2KnYQFO2BsFQEyoxcQylnXvmFT5NMYQ6w1DHmYlztkByZH7OW6 l3OinsmlTWIE8Q8DWkFXgXJXgb2nnY6/UJRlY+QR9mdBSWV3EC+y5NBrK0jB33GudKpKik9CQyKeA mEuzDGag==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lyfQy-00F3tm-PU; Wed, 30 Jun 2021 18:59:40 +0000 Received: from mail-pg1-f177.google.com ([209.85.215.177]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lyfQt-00F3sU-Tw for linux-nvme@lists.infradead.org; Wed, 30 Jun 2021 18:59:37 +0000 Received: by mail-pg1-f177.google.com with SMTP id w15so3234886pgk.13 for ; Wed, 30 Jun 2021 11:59:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=0Wi/OHievHiEkbKZk39MUJJHz8CqqbZiqlSseobXU1M=; b=i9kK+0b02kchmv9sgx2IavN8DzAzUxe/9a6QSWioMO8JsMuUwDw38ZaHqZ0KxCLnbw yL69JYnXUPuG6Bqo49bocxlSLM/p2AzUXbFxBGVFaGinBBTAAb5HzNti1hToIYRndP+d c1Rdk/0MryIMNDSpWF3Wyx0scy0cmuU4ZQdf3MgCzxz2wVr2HurnLHSGhl1K4Jy+xAx7 PfN8q6UN4X5MteXYMDjZjeVnE/rGIwELLHL6SJ41zJxogBQ3bLS+JOVM+SUXEb55lRjw 5nr76Lfn96LjyTtKx1QJbusjElUioD0xBhAGF/BlKmO5sowGBEVwW99KO/eABdKRLxUn ZtHw== X-Gm-Message-State: AOAM533GOBOFDxgpNvMKPklcderAXVr59niv82jFD/hMRfM7HmChmynk l3HoD2Vu2xk5pKvW4NCUU7w= X-Google-Smtp-Source: ABdhPJy5tD0xCLQMXKqgVzsGUSIoGa7yBsH1MnAew8zlYGkpf2YhN3yoWG+sZC4S96FcwF5kZZ03gw== X-Received: by 2002:a63:b0b:: with SMTP id 11mr35524933pgl.341.1625079575156; Wed, 30 Jun 2021 11:59:35 -0700 (PDT) Received: from ?IPv6:2601:647:4802:9070:8e5:b428:30c3:f97b? ([2601:647:4802:9070:8e5:b428:30c3:f97b]) by smtp.gmail.com with ESMTPSA id c24sm22501230pfd.167.2021.06.30.11.59.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 30 Jun 2021 11:59:34 -0700 (PDT) Subject: Re: [PATCH 0/2] blk-mq: fix blk_mq_alloc_request_hctx To: Ming Lei , Hannes Reinecke Cc: Jens Axboe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Christoph Hellwig , Daniel Wagner , Wen Xiong , John Garry References: <20210629074951.1981284-1-ming.lei@redhat.com> <5f304121-38ce-034b-2d17-93d136c77fe6@suse.de> From: Sagi Grimberg Message-ID: Date: Wed, 30 Jun 2021 11:59:33 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210630_115936_049990_B4BD9A2E X-CRM114-Status: GOOD ( 14.33 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org >>>> Shouldn't we rather modify the tagset to only refer to the current online >>>> CPUs _only_, thereby never submit a connect request for hctx with only >>>> offline CPUs? >>> >>> Then you may setup very less io queues, and performance may suffer even >>> though lots of CPUs become online later. >>> ; >> Only if we stay with the reduced number of I/O queues. Which is not what I'm >> proposing; I'd rather prefer to connect and disconnect queues from the cpu >> hotplug handler. For starters we could even trigger a reset once the first >> cpu within a hctx is onlined. > > Yeah, that need one big/complicated patchset, but not see any advantages > over this simple approach. I tend to agree with Ming here. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme