On 9/28/22 7:23 AM, Anuj gupta wrote: > On Tue, Sep 27, 2022 at 7:14 AM Jens Axboe <axboe@xxxxxxxxx> wrote: >> >> Hi, >> >> The passthrough IO path currently doesn't do any request allocation >> batching like we do for normal IO. Wire this up through the usual >> blk_mq_alloc_request() allocation helper. >> >> Similarly, we don't currently supported batched completions for >> passthrough IO. Allow the request->end_io() handler to return back >> whether or not it retains ownership of the request. By default all >> handlers are converted to returning RQ_END_IO_NONE, which retains >> the existing behavior. But with that in place, we can tweak the >> nvme uring_cmd end_io handler to pass back ownership, and hence enable >> completion batching for passthrough requests as well. >> >> This is good for a 10% improvement for passthrough performance. For >> a non-drive limited test case, passthrough IO is now more efficient >> than the regular bdev O_DIRECT path. >> >> Changes since v1: >> - Remove spurious semicolon >> - Cleanup struct nvme_uring_cmd_pdu handling >> >> -- >> Jens Axboe >> >> > I see an improvement of ~12% (2.34 to 2.63 MIOPS) with polling enabled and > an improvement of ~4% (1.84 to 1.92 MIOPS) with polling disabled using the > t/io_uring utility (in fio) in my setup with this patch series! Thanks for your testing! I'll add your reviewed-by to the series. -- Jens Axboe
