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([2600:1700:65a0:78e0:514:7862:1503:8e4d]) by smtp.gmail.com with ESMTPSA id t21sm1377896otr.42.2020.02.11.09.22.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 11 Feb 2020 09:22:09 -0800 (PST) Subject: Re: [PATCH RESEND V2 1/2] nvmet: allow block device to use buffered I/O To: Chaitanya Kulkarni , linux-nvme@lists.infradead.org References: <20200205020120.22210-1-chaitanya.kulkarni@wdc.com> <20200205020120.22210-2-chaitanya.kulkarni@wdc.com> From: Sagi Grimberg Message-ID: <7ce00b55-2e34-2784-5ff8-6b516e2adc85@grimberg.me> Date: Tue, 11 Feb 2020 09:22:07 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200205020120.22210-2-chaitanya.kulkarni@wdc.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200211_092212_794066_9F021A6E X-CRM114-Status: GOOD ( 16.05 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: MRuijter@onestopsystems.com, hch@lst.de 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 On 2/4/20 6:01 PM, Chaitanya Kulkarni wrote: > NVMeOF target already has a support to execute requests in the > buffered I/O mode with file backend. This patch allows block devices to > be used with file backend code so that buffered I/O parameter can be set > for a block device backed namespace when newly introduce configfs > parameter backeend. The new file defaults to the blockio user can switch > between "blockio" and "fileio" strings to enable the file backend for > the block device when buffered_io set to 1. > > Following is the performance improvement when backend=fileio and > buffered_io=1 :- > > Device_path = /dev/nullb0, I/O type = randread. > > With this patch and buffered I/O = 0: > read: IOPS=198k, BW=772MiB/s (809MB/s)(45.2GiB/60002msec) > read: IOPS=198k, BW=774MiB/s (811MB/s)(45.3GiB/60002msec) > read: IOPS=197k, BW=771MiB/s (808MB/s)(45.2GiB/60002msec) > > With this patch and buffered I/O = 1: > read: IOPS=979k, BW=3825MiB/s (4010MB/s)(224GiB/60002msec) > read: IOPS=983k, BW=3841MiB/s (4028MB/s)(225GiB/60003msec) > read: IOPS=980k, BW=3828MiB/s (4014MB/s)(224GiB/60002msec) > Chaitanya, Can you explain the difference here? null_blk literally does not do anything but complete the I/O, how does this patch improve so much? _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme