On 12/21/19 9:20 AM, Pavel Begunkov wrote: > On 21/12/2019 19:15, Pavel Begunkov wrote: >> Double account ctx->refs keeping number of taken refs in ctx. As >> io_uring gets per-request ctx->refs during submission, while holding >> ctx->uring_lock, this allows in most of the time to bypass >> percpu_ref_get*() and its overhead. > > Jens, could you please benchmark with this one? Especially for offloaded QD1 > case. I haven't got any difference for nops test and don't have a decent SSD > at hands to test it myself. We could drop it, if there is no benefit. > > This rewrites that @extra_refs from the second one, so I left it for now. Sure, let me run a peak test, qd1 test, qd1+sqpoll test on for-5.6/io_uring, same branch with 1-2, and same branch with 1-3. That should give us a good comparison. One core used for all, and we're going to be core speed bound for the performance in all cases on this setup. So it'll be a good comparison. -- Jens Axboe
