Re: [PATCH v6 2/2] dm: support bio polling

Jens Axboe
2022-03-10T04:06:35Z

On 3/9/22 9:00 PM, Ming Lei wrote:
> Looks improvement on 4k is small, is it caused by pcie bw limit?
> What is the IOPS when running the same t/io_uring on single optane
> directly?

Yes, see what you responded to higher up:

"which ends up being bw limited for me, because the devices aren't
linked gen4".

Some of them are, but the adapters are a bit janky and we often end up
with gen3 links and hence limited to ~3.2GB/sec per drive. But with the
bw limits even on gen4, you're roughly at about 1.5M IOPS per drive at
that point, so would expect lower percentage wise gains for 4k with
polling.

--
Jens Axboe