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To: Xiaobing Li , miklos@szeredi.hu Cc: linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, bschubert@ddn.com, kbusch@kernel.org, amir73il@gmail.com, asml.silence@gmail.com, dw@davidwei.uk, josef@toxicpanda.com, joannelkoong@gmail.com, tom.leiming@gmail.com, joshi.k@samsung.com, kun.dou@samsung.com, peiwei.li@samsung.com, xue01.he@samsung.com References: <20251020080043.6638-1-xiaobing.li@samsung.com> Content-Language: en-US From: Jens Axboe In-Reply-To: <20251020080043.6638-1-xiaobing.li@samsung.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/20/25 2:00 AM, Xiaobing Li wrote: > DDN has enabled Fuse to support the io-uring solution, allowing us > to implement zero copy on this basis to further improve performance. > > We have currently implemented zero copy using io-uring's fixed-buf > feature, further improving Fuse read performance. The general idea is > to first register a shared memory space through io_uring. > Then, libfuse in user space directly stores the read data into > the registered memory. The kernel then uses the io_uring_cmd_import_fixed > interface to directly retrieve the read results from the > shared memory, eliminating the need to copy data from user space to > kernel space. > > The test data is as follows: > > 4K IO size gain > ------------------------------------------------------------------------- > | no zero copy | zero copy | > rw iodepth numjobs | IOPS | IOPS | > read 1 1 | 93K | 97K | 1.04 > read 16 16 | 169K | 172K | 1.02 > read 16 32 | 172K | 173K | 1.01 > read 32 16 | 169K | 171K | 1.01 > read 32 32 | 172K | 173K | 1.01 > randread 1 1 | 116K | 136K | 1.17 > randread 1 32 | 985K | 994K | 1.01 > randread 64 1 | 234K | 261K | 1.12 > randread 64 16 | 166K | 168K | 1.01 > randread 64 32 | 168K | 170K | 1.01 > > 128K IO size gain > ------------------------------------------------------------------------- > | no zero copy | zero copy | > rw iodepth numjobs | IOPS | IOPS | > read 1 1 | 24K | 28K | 1.17 > read 16 1 | 17K | 19K | 1.12 > read 64 1 | 17K | 19K | 1.12 > read 64 16 | 51K | 55K | 1.08 > read 64 32 | 54K | 56K | 1.04 > randread 1 1 | 24K | 25K | 1.04 > randread 16 1 | 17K | 19K | 1.12 > randread 64 1 | 16K | 19K | 1.19 > randread 64 16 | 50K | 54K | 1.08 > randread 64 32 | 49K | 55K | 1.12 > ------------------------------------------------------------------------- > > I will list the code after this solution is confirmed to be feasible. Can you post the patches? A bit hard to tell if something is feasible or the right direction without them :-) -- Jens Axboe