On Mon, May 01, 2023 at 08:33:03AM -0700, Keith Busch wrote:
From: Keith Busch <kbusch@xxxxxxxxxx>
When you disable all the optional features in your kernel config and
request queue, it looks like the normal request dispatching is just as
fast as any attempts to bypass it.
Did a quick run, and it is not the case.
For that workload [1], this one moves to 3.4M from 3M.
While pure bypass moved to 5M from 3M. Maybe it could have gone higher
than 5M (which was the HW limit); have not checked that part yet.
[1]
# t/io_uring -b512 -d64 -c2 -s2 -p1 -F1 -B1 -O0 -n1 -u1 -r4 -k0 /dev/ng0n1
submitter=0, tid=2935, file=/dev/ng0n1, node=-1
polled=1, fixedbufs=1/0, register_files=1, buffered=1, register_queues=0 QD=64
Engine=io_uring, sq_ring=64, cq_ring=64
IOPS=3.31M, BW=1616MiB/s, IOS/call=2/1
IOPS=3.36M, BW=1642MiB/s, IOS/call=2/2
IOPS=3.40M, BW=1661MiB/s, IOS/call=2/1
Exiting on timeout
Maximum IOPS=3.40M
