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 D23FEC433F5 for ; Wed, 23 Mar 2022 02:17:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241141AbiCWCTY (ORCPT ); Tue, 22 Mar 2022 22:19:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59386 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231443AbiCWCTX (ORCPT ); Tue, 22 Mar 2022 22:19:23 -0400 Received: from mail-pl1-x632.google.com (mail-pl1-x632.google.com [IPv6:2607:f8b0:4864:20::632]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD1597006C for ; Tue, 22 Mar 2022 19:17:53 -0700 (PDT) Received: by mail-pl1-x632.google.com with SMTP id q11so250941pln.11 for ; Tue, 22 Mar 2022 19:17:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=eI61FWNjxNcvotxhTa64BG5fyhSEhuZwOn+ohZrc1yY=; b=k/h5WsdCLzhFU8jtxU82HEPtB6IfaSlxfKST3cuVgAwxE7RbWtEC/WRhGlR4qif4+6 DzCiLrzDzVVK0DtpcO6+wC8OXBhB04beACK7zsWp+5a6ImcpZ9RikSOI4lyXtlILvy0N 35oclVAPRwg+HB/yYntPrGdIDEmbEg81ihaEE9Wasmlt2u0fiv5uEym3POmJ2tzebH81 mD9QgeOPCGH4dgN/VHGtfRn+8qReXCBTtNRy/MoZzOOA1yECD/0Vm4OrNCvXjgUc0j7h 9TBp1tR9XftXsvDTcVOOje80fDDR19xw0IuMs1PTgMyml8qygT+jv7X6b/OGQJ7b+XRq 0fTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=eI61FWNjxNcvotxhTa64BG5fyhSEhuZwOn+ohZrc1yY=; b=fm/BAk5qM8fLvAwTOjpIJWfkqQzGsUG5CoYbzIrQ94RuKWPeBjDBWf1+WaRlslaEE+ 3qWsagsTdJCCo1cI4/OXYiqowbazdCPfCo9yqiAZJjHoKqy4WaybdLTez0A8/fL0CPsO zOVkBKIy4JWmbXRUVAtELpTy+wRmYd8TVk2XszpsDjbC60LvHjRaYX3RAlCpHzFRrfv9 bvhSqxOs7YeuyAVxIa78MesOArVf5bttTMJojS7a8fXyN3ior5+c4hLybawJxbc5OYpf Xltc4deRTOI5bnZkFHdM/qGv+lmZc0xn02ZOXGYdjgmS/Uu6c2fw7KtK05CFa7w80jYa 7Rlw== X-Gm-Message-State: AOAM532CsRSUvRWwUJm+efc3N+T8EkVt8JSetGdIWsRhJZKWYstPfSD1 YIX/HEKoeqtaS1Bs1ehVBDvqIg== X-Google-Smtp-Source: ABdhPJxtpgQpvbh5V5/2fg02qSRoT2lKlieuvf0XA4fL90y0FXVYDPKsEYxGzFPH4mzGlClL2NkgQg== X-Received: by 2002:a17:902:d2ce:b0:154:2e33:5663 with SMTP id n14-20020a170902d2ce00b001542e335663mr19559776plc.141.1648001873157; Tue, 22 Mar 2022 19:17:53 -0700 (PDT) Received: from [192.168.1.100] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id y13-20020a63b50d000000b0038297275c00sm5579534pge.34.2022.03.22.19.17.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Mar 2022 19:17:52 -0700 (PDT) Message-ID: Date: Tue, 22 Mar 2022 20:17:50 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH 10/17] block: wire-up support for plugging Content-Language: en-US To: Ming Lei Cc: Kanchan Joshi , Kanchan Joshi , Christoph Hellwig , Keith Busch , Pavel Begunkov , io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, sbates@raithlin.com, logang@deltatee.com, Pankaj Raghav , =?UTF-8?Q?Javier_Gonz=c3=a1lez?= , Luis Chamberlain , Adam Manzanares , Anuj Gupta References: <20220308152105.309618-1-joshi.k@samsung.com> <20220308152105.309618-11-joshi.k@samsung.com> <20220310083400.GD26614@lst.de> <20220321070208.GA5107@test-zns> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 3/22/22 8:10 PM, Ming Lei wrote: > On Tue, Mar 22, 2022 at 07:58:25PM -0600, Jens Axboe wrote: >> On 3/22/22 7:41 PM, Jens Axboe wrote: >>> On 3/22/22 7:27 PM, Ming Lei wrote: >>>> On Mon, Mar 21, 2022 at 12:32:08PM +0530, Kanchan Joshi wrote: >>>>> On Mon, Mar 14, 2022 at 10:40:53PM +0800, Ming Lei wrote: >>>>>> On Thu, Mar 10, 2022 at 06:10:08PM +0530, Kanchan Joshi wrote: >>>>>>> On Thu, Mar 10, 2022 at 2:04 PM Christoph Hellwig wrote: >>>>>>>> >>>>>>>> On Tue, Mar 08, 2022 at 08:50:58PM +0530, Kanchan Joshi wrote: >>>>>>>>> From: Jens Axboe >>>>>>>>> >>>>>>>>> Add support to use plugging if it is enabled, else use default path. >>>>>>>> >>>>>>>> The subject and this comment don't really explain what is done, and >>>>>>>> also don't mention at all why it is done. >>>>>>> >>>>>>> Missed out, will fix up. But plugging gave a very good hike to IOPS. >>>>>> >>>>>> But how does plugging improve IOPS here for passthrough request? Not >>>>>> see plug->nr_ios is wired to data.nr_tags in blk_mq_alloc_request(), >>>>>> which is called by nvme_submit_user_cmd(). >>>>> >>>>> Yes, one tag at a time for each request, but none of the request gets >>>>> dispatched and instead added to the plug. And when io_uring ends the >>>>> plug, the whole batch gets dispatched via ->queue_rqs (otherwise it used >>>>> to be via ->queue_rq, one request at a time). >>>>> >>>>> Only .plug impact looks like this on passthru-randread: >>>>> >>>>> KIOPS(depth_batch) 1_1 8_2 64_16 128_32 >>>>> Without plug 159 496 784 785 >>>>> With plug 159 525 991 1044 >>>>> >>>>> Hope it does clarify. >>>> >>>> OK, thanks for your confirmation, then the improvement should be from >>>> batch submission only. >>>> >>>> If cached request is enabled, I guess the number could be better. >>> >>> Yes, my original test patch pre-dates being able to set a submit count, >>> it would definitely help improve this case too. The current win is >>> indeed just from being able to use ->queue_rqs() rather than single >>> submit. >> >> Actually that is already there through io_uring, nothing extra is >> needed. > > I meant in this patchset that plug->nr_ios isn't wired to data.nr_tags in > blk_mq_alloc_request(), which is called by pt request allocation, so > looks cached request isn't enabled for pt commands? My point is that it is, since submission is through io_uring which does exactly that. -- Jens Axboe