Hi Hannes, On Mon, Mar 06, 2023 at 01:01:22PM +0100, Hannes Reinecke wrote: > Hi all, > > meat to the bone: with this patchset one can change the physical and > logical block size of the 'brd' ramdisk driver. > Default is 512 (for both); one can easily increase the physical block > size to 16k and the logical block size to 4k. > Increasing the logcial block size beyond 4k gives some 'interesting' > crashes. I did something similar for an internal prototype to test large block size. I ran the perf test suite I created on your changes and I can clearly see a perf increase for large block IOs. I enabled huge pages and used the iomem=mmaphuge option in fio to test large block IOs. Here are my results: base: next-20230307 new: base with your changes on top bw: bandwith in MiB/s For each set of rd_blksize and rd_logical_blksize, I ran the test with different fio blocksize as indicated by `io_uring_iod_128_bs_4k` rd_blksize=8192 and rd_logical_blksize=4096 +------------------------+-------------+------------+-------+----------+---------+-------+ | io_uring_iod_128_bs_4k | base[kiops] | new[kiops] | delta | base[bw] | new[bw] | delta | +------------------------+-------------+------------+-------+----------+---------+-------+ | read | 567 | 605 | 6.7 | 2214 | 2362 | 6.68 | | randread | 517 | 529 | 2.32 | 2019 | 2066 | 2.33 | | write | 551 | 558 | 1.27 | 2154 | 2179 | 1.16 | | randwrite | 481 | 502 | 4.37 | 1880 | 1962 | 4.36 | +------------------------+-------------+------------+-------+----------+---------+-------+ +------------------------+-------------+------------+-------+----------+---------+-------+ | io_uring_iod_128_bs_8k | base[kiops] | new[kiops] | delta | base[bw] | new[bw] | delta | +------------------------+-------------+------------+-------+----------+---------+-------+ | read | 462 | 512 | 10.82 | 3611 | 3997 | 10.69 | | randread | 426 | 445 | 4.46 | 3326 | 3480 | 4.63 | | write | 442 | 472 | 6.79 | 3454 | 3687 | 6.75 | | randwrite | 401 | 426 | 6.23 | 3134 | 3328 | 6.19 | +------------------------+-------------+------------+-------+----------+---------+-------+ +-------------------------+-------------+------------+-------+----------+---------+-------+ | io_uring_iod_128_bs_16k | base[kiops] | new[kiops] | delta | base[bw] | new[bw] | delta | +-------------------------+-------------+------------+-------+----------+---------+-------+ | read | 343 | 390 | 13.7 | 5360 | 6086 | 13.54 | | randread | 317 | 364 | 14.83 | 4946 | 5694 | 15.12 | | write | 335 | 346 | 3.28 | 5235 | 5414 | 3.42 | | randwrite | 305 | 327 | 7.21 | 4759 | 5106 | 7.29 | +-------------------------+-------------+------------+-------+----------+---------+-------+ rd_blksize=16384 and rd_logical_blksize=4096 +------------------------+-------------+------------+-------+----------+---------+-------+ | io_uring_iod_128_bs_4k | base[kiops] | new[kiops] | delta | base[bw] | new[bw] | delta | +------------------------+-------------+------------+-------+----------+---------+-------+ | read | 576 | 586 | 1.74 | 2250 | 2291 | 1.82 | | randread | 524 | 548 | 4.58 | 2046 | 2139 | 4.55 | | write | 533 | 545 | 2.25 | 2081 | 2129 | 2.31 | | randwrite | 484 | 496 | 2.48 | 1892 | 1938 | 2.43 | +------------------------+-------------+------------+-------+----------+---------+-------+ +------------------------+-------------+------------+-------+----------+---------+-------+ | io_uring_iod_128_bs_8k | base[kiops] | new[kiops] | delta | base[bw] | new[bw] | delta | +------------------------+-------------+------------+-------+----------+---------+-------+ | read | 461 | 491 | 6.51 | 3601 | 3836 | 6.53 | | randread | 425 | 472 | 11.06 | 3323 | 3684 | 10.86 | | write | 454 | 465 | 2.42 | 3543 | 3632 | 2.51 | | randwrite | 395 | 430 | 8.86 | 3086 | 3357 | 8.78 | +------------------------+-------------+------------+-------+----------+---------+-------+ +-------------------------+-------------+------------+-------+----------+---------+-------+ | io_uring_iod_128_bs_16k | base[kiops] | new[kiops] | delta | base[bw] | new[bw] | delta | +-------------------------+-------------+------------+-------+----------+---------+-------+ | read | 338 | 400 | 18.34 | 5282 | 6255 | 18.42 | | randread | 317 | 384 | 21.14 | 4959 | 5997 | 20.93 | | write | 335 | 354 | 5.67 | 5239 | 5525 | 5.46 | | randwrite | 303 | 326 | 7.59 | 4728 | 5097 | 7.8 | +-------------------------+-------------+------------+-------+----------+---------+-------+
