On Thu, Sep 01, 2022 at 08:17:47PM -0400, Kent Overstreet wrote:

On Thu, Sep 01, 2022 at 03:53:57PM -0700, Roman Gushchin wrote:

quoted

I'd suggest to run something like iperf on a fast hardware. And maybe some
io_uring stuff too. These are two places which were historically most sensitive
to the (kernel) memory accounting speed.

I'm getting wildly inconsistent results with iperf.

io_uring-echo-server and rust_echo_bench gets me:
Benchmarking: 127.0.0.1:12345
50 clients, running 512 bytes, 60 sec.

Without alloc tagging:	120547 request/sec
With:			116748 request/sec

https://github.com/frevib/io_uring-echo-server
https://github.com/haraldh/rust_echo_bench

How's that look to you? Close enough? :)

Yes, this looks good (a bit too good).

I'm not that familiar with io_uring, Jens and Pavel should have a better idea
what and how to run (I know they've workarounded the kernel memory accounting
because of the performance in the past, this is why I suspect it might be an
issue here as well).

This is a recent optimization on the networking side:
https://lore.kernel.org/linux-mm/20220825000506.239406-1-shakeelb@google.com/ (local)

Maybe you can try to repeat this experiment.

Thanks!