On 4/22/24 18:11, Jens Axboe wrote: >On 4/18/24 3:31 AM, hexue wrote: >> This patch is intended to release the CPU resources of io_uring in >> polling mode. When IO is issued, the program immediately polls for >> check completion, which is a waste of CPU resources when IO commands >> are executed on the disk. >> >> I add the hybrid polling feature in io_uring, enables polling to >> release a portion of CPU resources without affecting block layer. >> >> - Record the running time and context switching time of each >> IO, and use these time to determine whether a process continue >> to schedule. >> >> - Adaptive adjustment to different devices. Due to the real-time >> nature of time recording, each device's IO processing speed is >> different, so the CPU optimization effect will vary. >> >> - Set a interface (ctx->flag) enables application to choose whether >> or not to use this feature. >> >> The CPU optimization in peak workload of patch is tested as follows: >> all CPU utilization of original polling is 100% for per CPU, after >> optimization, the CPU utilization drop a lot (per CPU); >> >> read(128k, QD64, 1Job) 37% write(128k, QD64, 1Job) 40% >> randread(4k, QD64, 16Job) 52% randwrite(4k, QD64, 16Job) 12% >> >> Compared to original polling, the optimised performance reduction >> with peak workload within 1%. >> >> read 0.29% write 0.51% randread 0.09% randwrite 0% > >As mentioned, this is like a reworked version of the old hybrid polling >we had. The feature itself may make sense, but there's a slew of things >in this patch that aren't really acceptable. More below. Thank you very much for your patience in reviewing and correcting, I will improve those as soon as possible and submit the v3 patch later.
