Re: [PATCH v1 00/15] io_uring zero copy rx

David Ahern
2024-10-09T16:35:44Z

On 10/9/24 9:43 AM, Jens Axboe wrote:
> Yep basically line rate, I get 97-98Gbps. I originally used a slower box
> as the sender, but then you're capped on the non-zc sender being too
> slow. The intel box does better, but it's still basically maxing out the
> sender at this point. So yeah, with a faster (or more efficient sender),

I am surprised by this comment. You should not see a Tx limited test
(including CPU bound sender). Tx with ZC has been the easy option for a
while now.

> I have no doubts this will go much higher per thread, if the link bw was
> there. When I looked at CPU usage for the receiver, the thread itself is
> using ~30% CPU. And then there's some softirq/irq time outside of that,
> but that should ammortize with higher bps rates too I'd expect.
>
> My nic does have 2 100G ports, so might warrant a bit more testing...
>

It would be good to see what the next bottleneck is for io_uring with ZC
Rx path. My expectation is that a 200G link is a means to show you (ie.,
you will not hit 200G so cpu monitoring, perf-top, etc will show the
limiter).