On 3/18/22 9:00 AM, Pavel Begunkov wrote: > On 3/18/22 14:52, Jens Axboe wrote: >> On 3/18/22 8:42 AM, Pavel Begunkov wrote: >>> On 3/18/22 13:52, Pavel Begunkov wrote: >>>> A WIP feature optimising out CQEs posting spinlocking for some use cases. >>>> For a more detailed description see 4/4. >>>> >>>> Quick benchmarking with fio/t/io_uring nops gives extra 4% to throughput for >>>> QD=1, and ~+2.5% for QD=4. >>> >>> Non-io_uring overhead (syscalls + userspace) takes ~60% of all execution >>> time, so the percentage should quite depend on the CPU and the kernel config. >>> Likely to be more than 4% for a faster setup. >>> >>> fwiw, was also usingIORING_ENTER_REGISTERED_RING, if it's not yet included >>> in the upstream version of the tool. >> >> But that seems to be exclusive of using PRIVATE_CQ? > > No, it's not. Let me ask to clarify the description and so, why do you > think it is exclusive? Didn't dig too deep, just saw various EINVAL around registered files and updating/insertion. And the fact that t/io_uring gets -EINVAL on register with op 20 (ring fd) if I set CQ_PRIVATE, see other email. -- Jens Axboe
