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Mon, 21 Mar 2022 16:23:16 +0900 (KST) Received: from epsmtrp1.samsung.com (unknown [182.195.40.13]) by epcas5p1.samsung.com (KnoxPortal) with ESMTPA id 20220321070713epcas5p1826cc38562ac865cc1deff8b2c6fda41~eU5mt68lG0400904009epcas5p1-; Mon, 21 Mar 2022 07:07:13 +0000 (GMT) Received: from epsmgms1p1new.samsung.com (unknown [182.195.42.41]) by epsmtrp1.samsung.com (KnoxPortal) with ESMTP id 20220321070713epsmtrp1735ef0e08fb0a5cc56965857c3c9666b~eU5ms4IZG1883718837epsmtrp1R; Mon, 21 Mar 2022 07:07:13 +0000 (GMT) X-AuditID: b6c32a4a-5b7ff700000030eb-fe-623827e4b334 Received: from epsmtip2.samsung.com ( [182.195.34.31]) by epsmgms1p1new.samsung.com (Symantec Messaging Gateway) with SMTP id 3C.22.29871.02428326; Mon, 21 Mar 2022 16:07:12 +0900 (KST) Received: from test-zns (unknown [107.110.206.5]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20220321070710epsmtip27cc547b5b0ccf510e7767bb286ed7a07~eU5kTmEwD0845808458epsmtip2T; Mon, 21 Mar 2022 07:07:10 +0000 (GMT) Date: Mon, 21 Mar 2022 12:32:08 +0530 From: Kanchan Joshi To: Ming Lei Cc: Kanchan Joshi , Christoph Hellwig , Jens Axboe , 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 , Javier =?utf-8?B?R29uesOhbGV6?= , Luis Chamberlain , Adam Manzanares , Anuj Gupta Subject: Re: [PATCH 10/17] block: wire-up support for plugging Message-ID: <20220321070208.GA5107@test-zns> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Brightmail-Tracker: H4sIAAAAAAAAA02Te0xTVxzHc+7tC1iXuwLhWOPEq8tWWKGVtlyQxxLddjfZQpjLlv0hXOCm ZdBH+sAHERGCCpGH4AQ6LDAoC4+g8mgYDIcFAwjDx1AGCMNBGbiJVTa2gZi1tCz+9znf3/d3 fuf8fudwUN4ci89JUelprYpKw1meDEuf4C3h/JtEomjOJiTK+nYR2cUbKFHZaAFE03QRi2ho uoEQy7mjDCJv+DZC3HrchxAl1vuA6JkMJKrqbWyiLneARfxcbAOEtTQHIZonbAxiZcTEfAcj F+4tAPI74zSbzKl+wCB/+tFAtjbmsci2upNk90QWi7TULjHJJ9fuscjC9kZArrS+Huv1RWqE gqaSaa0/rUpSJ6eo5JH4wU/i98dLZSKxUBxGhOL+KkpJR+IHYmKF76WkOW6D+6dTaQaHFEvp dHhwVIRWbdDT/gq1Th+J05rkNI1EE6SjlDqDSh6kovXhYpFor9RhTEhVPM+dYGlmXzn6zeIk kgUueuYDDw7EJPDPX2pBPvDk8LBuADvX+1HX4hmAIyu97sgqgA32u+hWSmnLEtsV6AHQ3HHO vVgAcLjtL+B0MbA34NPpfCQfcDgsTABvlxqcsg+Gw+nppk0/ihUy4Nk7pk2/NxYFi9ZymU4/ F3sb9p466pS52GtwqGKe4WQPbA80jT5GnOyL7Ya9lgHEuQ/EFjmwouMf4DrdAVj2bMbN3vDR QDvbxXy4VHTazTq49uAG6ko+C+B4VgXDFYiGd77f2KyAYimweaSD5dJ3wK9utrj1V2HB+jzi 0rmw07TFu+BMiY3pYj/4sLzOzSSc/+P6Zut42HUE9nVIisFO40uXM75UzsXhMM+ezTQ6eoFi 2+G3LzguFMDLXcHVgNkIttEanVJO66SavSr6yP8TT1IrW8Hmaw/4sBM8nLUHWQHCAVYAOSju w621hybyuMnUseO0Vh2vNaTROiuQOmZ1HuX7Jqkd30WljxdLwkQSmUwmCQuRiXE/7rD8CsXD 5JSeTqVpDa3dykM4HvwspGtREEiFZyvIfxWWw79/dqLA6zwtOlnix2+rW1uwnbkMplZjBr8c Nx9uCeg2vb+q3Hbuwg9dd8vSo/fVHyQSxg716zuVkOG9xsx5+vm+mcCuXqm5wSorjxsdDxF2 FI1NeW8Psn+9OrfnQmV4j1WY98gcMpjb3zUv5lcPeQTWjF2VF/QyPfOqKvYXiGrK6zdk5laf TFt1dBwvcdmXbfxoNpzX5rX85FjmccHNIeOMdOHSuteJbm7lTs21T9+9j04JfosSZJTLVFWT wrj250f4H7xQpQsv+siHg2N3j5xi+3XfunQowRKBXz2dEdrQkOFtjvm70Z45XtM8+PEVxo4z hb/iDJ2CEgegWh31H6hDUD52BAAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrMIsWRmVeSWpSXmKPExsWy7bCSvK6CikWSwZsnNhbTDytaNE34y2wx Z9U2RovVd/vZLFauPspk8a71HItF5+kLTBbn3x5msph06Bqjxd5b2hbzlz1lt1jSepzN4saE p4wWhyY3M1msufmUxeLzmXmsDgIez64+Y/TYOesuu0fzgjssHpfPlnpsWtXJ5rF5Sb3H7psN bB7bFr9k9Xi/7yqbR9+WVYwenzfJBXBHcdmkpOZklqUW6dslcGXs2fOQraCfq+L9qyPMDYz3 2bsYOTkkBEwkJq97CWRzcQgJ7GaU6Hz1hBkiIS7RfO0HVJGwxMp/z8FsIYEnjBLr59SC2CwC qhIf73YxdTFycLAJaEpcmFwKEhYRUJK4e3c12ExmgUksEtfP3ADrFRawk+j/1coKUs8roCNx oLECYu9BJomrHSfZQGp4BQQlTs58wgJiMwuYSczb/JAZpJ5ZQFpi+T8OkDCngIrEvHNvmUBs UQFliQPbjjNNYBSchaR7FpLuWQjdCxiZVzFKphYU56bnFhsWGOallusVJ+YWl+al6yXn525i BMejluYOxu2rPugdYmTiYDzEKMHBrCTCu/iDeZIQb0piZVVqUX58UWlOavEhRmkOFiVx3gtd J+OFBNITS1KzU1MLUotgskwcnFINTJylLHu8t/8Isv/9/E/oHh8nBZf+j1PmbJZ+t+DBdpb6 O/XaYnaOcj/W1Hw89lT60233As3PfoIJeW/jPNxMquomnV7c7Db99uLsnsUn9JnvVtp2sYR8 THt1/u9tddOZwhrXX7xbrfFSnsE3R0RmpmLCkyzTi2++lvfkl97536Xx7OyB5GuXObiUf2bs eOxz5rx82r4dz/58VgwRUdTc1/2ZV8drDuurYy4+/Ee2uzu98I+cXFW3I+XlOvPepHPPHM7X tzUmNDYxMU2t+lZ068mxo6l3yo7tVrzaKbdw2/t6hvuvQxS2qX67cuO43z4RQ8UNtlqy/vPa 96S8vrLX2VS8ZL9xqg0ri+ZuXUbnEiWW4oxEQy3mouJEADTvNOY2AwAA X-CMS-MailID: 20220321070713epcas5p1826cc38562ac865cc1deff8b2c6fda41 X-Msg-Generator: CA Content-Type: multipart/mixed; boundary="----.rW42XXn7_Ji6OxwuAF4RAMbP.qed.OeqKlvEhSLhB3noATS=_1325e8_" X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20220308152714epcas5p4c5a0d16512fd7054c9a713ee28ede492 References: <20220308152105.309618-1-joshi.k@samsung.com> <20220308152105.309618-11-joshi.k@samsung.com> <20220310083400.GD26614@lst.de> Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org ------.rW42XXn7_Ji6OxwuAF4RAMbP.qed.OeqKlvEhSLhB3noATS=_1325e8_ Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Disposition: inline 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. ------.rW42XXn7_Ji6OxwuAF4RAMbP.qed.OeqKlvEhSLhB3noATS=_1325e8_ Content-Type: text/plain; charset="utf-8" ------.rW42XXn7_Ji6OxwuAF4RAMbP.qed.OeqKlvEhSLhB3noATS=_1325e8_--