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[109.152.100.135]) by smtp.gmail.com with ESMTPSA id c187sm1854796wmd.23.2020.11.23.15.45.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 23 Nov 2020 15:45:43 -0800 (PST) To: David Howells , Christoph Hellwig Cc: Matthew Wilcox , Jens Axboe , Alexander Viro , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <20201123080506.GA30578@infradead.org> <160596800145.154728.7192318545120181269.stgit@warthog.procyon.org.uk> <160596801020.154728.15935034745159191564.stgit@warthog.procyon.org.uk> <516984.1606127474@warthog.procyon.org.uk> From: Pavel Begunkov Autocrypt: addr=asml.silence@gmail.com; prefer-encrypt=mutual; keydata= mQINBFmKBOQBEAC76ZFxLAKpDw0bKQ8CEiYJRGn8MHTUhURL02/7n1t0HkKQx2K1fCXClbps bdwSHrhOWdW61pmfMbDYbTj6ZvGRvhoLWfGkzujB2wjNcbNTXIoOzJEGISHaPf6E2IQx1ik9 6uqVkK1OMb7qRvKH0i7HYP4WJzYbEWVyLiAxUj611mC9tgd73oqZ2pLYzGTqF2j6a/obaqha +hXuWTvpDQXqcOZJXIW43atprH03G1tQs7VwR21Q1eq6Yvy2ESLdc38EqCszBfQRMmKy+cfp W3U9Mb1w0L680pXrONcnlDBCN7/sghGeMHjGKfNANjPc+0hzz3rApPxpoE7HC1uRiwC4et83 CKnncH1l7zgeBT9Oa3qEiBlaa1ZCBqrA4dY+z5fWJYjMpwI1SNp37RtF8fKXbKQg+JuUjAa9 Y6oXeyEvDHMyJYMcinl6xCqCBAXPHnHmawkMMgjr3BBRzODmMr+CPVvnYe7BFYfoajzqzq+h EyXSl3aBf0IDPTqSUrhbmjj5OEOYgRW5p+mdYtY1cXeK8copmd+fd/eTkghok5li58AojCba jRjp7zVOLOjDlpxxiKhuFmpV4yWNh5JJaTbwCRSd04sCcDNlJj+TehTr+o1QiORzc2t+N5iJ NbILft19Izdn8U39T5oWiynqa1qCLgbuFtnYx1HlUq/HvAm+kwARAQABtDFQYXZlbCBCZWd1 bmtvdiAoc2lsZW5jZSkgPGFzbWwuc2lsZW5jZUBnbWFpbC5jb20+iQJOBBMBCAA4FiEE+6Ju PTjTbx479o3OWt5b1Glr+6UFAlmKBOQCGwMFCwkIBwIGFQgJCgsCBBYCAwECHgECF4AACgkQ Wt5b1Glr+6WxZA//QueaKHzgdnOikJ7NA/Vq8FmhRlwgtP0+E+w93kL+ZGLzS/cUCIjn2f4Q Mcutj2Neg0CcYPX3b2nJiKr5Vn0rjJ/suiaOa1h1KzyNTOmxnsqE5fmxOf6C6x+NKE18I5Jy xzLQoktbdDVA7JfB1itt6iWSNoOTVcvFyvfe5ggy6FSCcP+m1RlR58XxVLH+qlAvxxOeEr/e aQfUzrs7gqdSd9zQGEZo0jtuBiB7k98t9y0oC9Jz0PJdvaj1NZUgtXG9pEtww3LdeXP/TkFl HBSxVflzeoFaj4UAuy8+uve7ya/ECNCc8kk0VYaEjoVrzJcYdKP583iRhOLlZA6HEmn/+Gh9 4orG67HNiJlbFiW3whxGizWsrtFNLsSP1YrEReYk9j1SoUHHzsu+ZtNfKuHIhK0sU07G1OPN 2rDLlzUWR9Jc22INAkhVHOogOcc5ajMGhgWcBJMLCoi219HlX69LIDu3Y34uIg9QPZIC2jwr 24W0kxmK6avJr7+n4o8m6sOJvhlumSp5TSNhRiKvAHB1I2JB8Q1yZCIPzx+w1ALxuoWiCdwV M/azguU42R17IuBzK0S3hPjXpEi2sK/k4pEPnHVUv9Cu09HCNnd6BRfFGjo8M9kZvw360gC1 reeMdqGjwQ68o9x0R7NBRrtUOh48TDLXCANAg97wjPoy37dQE7e5Ag0EWYoE5AEQAMWS+aBV IJtCjwtfCOV98NamFpDEjBMrCAfLm7wZlmXy5I6o7nzzCxEw06P2rhzp1hIqkaab1kHySU7g dkpjmQ7Jjlrf6KdMP87mC/Hx4+zgVCkTQCKkIxNE76Ff3O9uTvkWCspSh9J0qPYyCaVta2D1 Sq5HZ8WFcap71iVO1f2/FEHKJNz/YTSOS/W7dxJdXl2eoj3gYX2UZNfoaVv8OXKaWslZlgqN jSg9wsTv1K73AnQKt4fFhscN9YFxhtgD/SQuOldE5Ws4UlJoaFX/yCoJL3ky2kC0WFngzwRF Yo6u/KON/o28yyP+alYRMBrN0Dm60FuVSIFafSqXoJTIjSZ6olbEoT0u17Rag8BxnxryMrgR dkccq272MaSS0eOC9K2rtvxzddohRFPcy/8bkX+t2iukTDz75KSTKO+chce62Xxdg62dpkZX xK+HeDCZ7gRNZvAbDETr6XI63hPKi891GeZqvqQVYR8e+V2725w+H1iv3THiB1tx4L2bXZDI DtMKQ5D2RvCHNdPNcZeldEoJwKoA60yg6tuUquvsLvfCwtrmVI2rL2djYxRfGNmFMrUDN1Xq F3xozA91q3iZd9OYi9G+M/OA01husBdcIzj1hu0aL+MGg4Gqk6XwjoSxVd4YT41kTU7Kk+/I 5/Nf+i88ULt6HanBYcY/+Daeo/XFABEBAAGJAjYEGAEIACAWIQT7om49ONNvHjv2jc5a3lvU aWv7pQUCWYoE5AIbDAAKCRBa3lvUaWv7pfmcEACKTRQ28b1y5ztKuLdLr79+T+LwZKHjX++P 4wKjEOECCcB6KCv3hP+J2GCXDOPZvdg/ZYZafqP68Yy8AZqkfa4qPYHmIdpODtRzZSL48kM8 LRzV8Rl7J3ItvzdBRxf4T/Zseu5U6ELiQdCUkPGsJcPIJkgPjO2ROG/ZtYa9DvnShNWPlp+R uPwPccEQPWO/NP4fJl2zwC6byjljZhW5kxYswGMLBwb5cDUZAisIukyAa8Xshdan6C2RZcNs rB3L7vsg/R8UCehxOH0C+NypG2GqjVejNZsc7bgV49EOVltS+GmGyY+moIzxsuLmT93rqyII 5rSbbcTLe6KBYcs24XEoo49Zm9oDA3jYvNpeYD8rDcnNbuZh9kTgBwFN41JHOPv0W2FEEWqe JsCwQdcOQ56rtezdCJUYmRAt3BsfjN3Jn3N6rpodi4Dkdli8HylM5iq4ooeb5VkQ7UZxbCWt UVMKkOCdFhutRmYp0mbv2e87IK4erwNHQRkHUkzbsuym8RVpAZbLzLPIYK/J3RTErL6Z99N2 m3J6pjwSJY/zNwuFPs9zGEnRO4g0BUbwGdbuvDzaq6/3OJLKohr5eLXNU3JkT+3HezydWm3W OPhauth7W0db74Qd49HXK0xe/aPrK+Cp+kU1HRactyNtF8jZQbhMCC8vMGukZtWaAwpjWiiH bA== Subject: Re: [PATCH 01/29] iov_iter: Switch to using a table of operations Message-ID: <74f6fb34-c4c2-6a7e-3614-78c34246c6bd@gmail.com> Date: Mon, 23 Nov 2020 23:42:35 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: <516984.1606127474@warthog.procyon.org.uk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 23/11/2020 10:31, David Howells wrote: > Christoph Hellwig wrote: > >> Please run performance tests. I think the indirect calls could totally >> wreck things like high performance direct I/O, especially using io_uring >> on x86. > > Here's an initial test using fio and null_blk. I left null_blk in its default > configuration and used the following command line: I'd prefer something along no_sched=1 submit_queues=$(nproc) to reduce overhead. > > fio --ioengine=libaio --direct=1 --gtod_reduce=1 --name=readtest --filename=/dev/nullb0 --bs=4k --iodepth=128 --time_based --runtime=120 --readwrite=randread --iodepth_low=96 --iodepth_batch=16 --numjobs=4 fio is relatively heavy, I'd suggest to try fio/t/io_uring with nullblk > > I borrowed some of the parameters from an email I found online, so I'm not > sure if they're that useful. > > I tried three different sets of patches: none, just the first (which adds the > jump table without getting rid of the conditional branches), and all of them. > > I'm not sure which stats are of particular interest here, so I took the two > summary stats from the output of fio and also added together the "issued rwts: > total=a,b,c,d" from each test thread (only the first of which is non-zero). > > The CPU is an Intel(R) Core(TM) i3-4170 CPU @ 3.70GHz, so 4 single-thread > cores, and 16G of RAM. No virtualisation is involved. > > Unpatched: > > READ: bw=4109MiB/s (4308MB/s), 1025MiB/s-1029MiB/s (1074MB/s-1079MB/s), io=482GiB (517GB), run=120001-120001msec > READ: bw=4097MiB/s (4296MB/s), 1020MiB/s-1029MiB/s (1070MB/s-1079MB/s), io=480GiB (516GB), run=120001-120001msec > READ: bw=4113MiB/s (4312MB/s), 1025MiB/s-1031MiB/s (1075MB/s-1082MB/s), io=482GiB (517GB), run=120001-120001msec > READ: bw=4125MiB/s (4325MB/s), 1028MiB/s-1033MiB/s (1078MB/s-1084MB/s), io=483GiB (519GB), run=120001-120001msec > > nullb0: ios=126017326/0, merge=53/0, ticks=3538817/0, in_queue=3538817, util=100.00% > nullb0: ios=125655193/0, merge=55/0, ticks=3548157/0, in_queue=3548157, util=100.00% > nullb0: ios=126133014/0, merge=58/0, ticks=3545621/0, in_queue=3545621, util=100.00% > nullb0: ios=126512562/0, merge=57/0, ticks=3531600/0, in_queue=3531600, util=100.00% > > sum issued rwts = 126224632 > sum issued rwts = 125861368 > sum issued rwts = 126340344 > sum issued rwts = 126718648 > > Just first patch: > > READ: bw=4106MiB/s (4306MB/s), 1023MiB/s-1030MiB/s (1073MB/s-1080MB/s), io=481GiB (517GB), run=120001-120001msec > READ: bw=4126MiB/s (4327MB/s), 1029MiB/s-1034MiB/s (1079MB/s-1084MB/s), io=484GiB (519GB), run=120001-120001msec > READ: bw=4109MiB/s (4308MB/s), 1025MiB/s-1029MiB/s (1075MB/s-1079MB/s), io=481GiB (517GB), run=120001-120001msec > READ: bw=4097MiB/s (4296MB/s), 1023MiB/s-1025MiB/s (1073MB/s-1074MB/s), io=480GiB (516GB), run=120001-120001msec > > nullb0: ios=125939152/0, merge=62/0, ticks=3534917/0, in_queue=3534917, util=100.00% > nullb0: ios=126554181/0, merge=61/0, ticks=3532067/0, in_queue=3532067, util=100.00% > nullb0: ios=126012346/0, merge=54/0, ticks=3530504/0, in_queue=3530504, util=100.00% > nullb0: ios=125653775/0, merge=54/0, ticks=3537438/0, in_queue=3537438, util=100.00% > > sum issued rwts = 126144952 > sum issued rwts = 126765368 > sum issued rwts = 126215928 > sum issued rwts = 125864120 > > All patches: > nullb0: ios=10477062/0, merge=2/0, ticks=284992/0, in_queue=284992, util=95.87% > nullb0: ios=10405246/0, merge=2/0, ticks=291886/0, in_queue=291886, util=99.82% > nullb0: ios=10425583/0, merge=1/0, ticks=291699/0, in_queue=291699, util=99.22% > nullb0: ios=10438845/0, merge=3/0, ticks=292445/0, in_queue=292445, util=99.31% > > READ: bw=4118MiB/s (4318MB/s), 1028MiB/s-1032MiB/s (1078MB/s-1082MB/s), io=483GiB (518GB), run=120001-120001msec > READ: bw=4109MiB/s (4308MB/s), 1024MiB/s-1030MiB/s (1073MB/s-1080MB/s), io=481GiB (517GB), run=120001-120001msec > READ: bw=4108MiB/s (4308MB/s), 1026MiB/s-1029MiB/s (1076MB/s-1079MB/s), io=481GiB (517GB), run=120001-120001msec > READ: bw=4112MiB/s (4312MB/s), 1025MiB/s-1031MiB/s (1075MB/s-1081MB/s), io=482GiB (517GB), run=120001-120001msec > > nullb0: ios=126282410/0, merge=58/0, ticks=3557384/0, in_queue=3557384, util=100.00% > nullb0: ios=126004837/0, merge=67/0, ticks=3565235/0, in_queue=3565235, util=100.00% > nullb0: ios=125988876/0, merge=59/0, ticks=3563026/0, in_queue=3563026, util=100.00% > nullb0: ios=126118279/0, merge=57/0, ticks=3566122/0, in_queue=3566122, util=100.00% > > sum issued rwts = 126494904 > sum issued rwts = 126214200 > sum issued rwts = 126198200 > sum issued rwts = 126328312 > > > David > -- Pavel Begunkov