On 2/14/23 7:48?AM, Pankaj Raghav wrote: > Hi Ming, > > On 2023-02-13 13:40, Ming Lei wrote: >>>> >>>> Can you share perf data on other non-io_uring engine often used? The >>>> thing is that we still have lots of non-io_uring workloads, which can't >>>> be hurt now. >>>> >>> Sounds good. Does psync and libaio along with io_uring suffice? >> >> Yeah, it should be enough. >> > > Performance regression is noticed for libaio and psync. I did the same > tests on null_blk with bio and blk-mq backends, and noticed a similar pattern. > > Should we add a module parameter to switch between bio and blk-mq back-end > in brd, similar to null_blk? The default option would be bio to avoid > regression on existing workloads. > > There is a clear performance gain for some workloads with blk-mq support in > brd. Let me know your thoughts. See below the performance results. > > Results for brd with --direct enabled: I think your numbers are skewed because brd isn't flagg nowait, can you try with this? I ran some quick testing here, using the current tree: without patch with patch io_uring ~430K IOPS ~3.4M IOPS libaio ~895K IOPS ~895K IOPS which is a pretty substantial difference... -- Jens Axboe
