Re: [PATCH net-next] net: skbuff: Skip early return in skb_unref when debugging

Jason Xing
2024-07-31T11:53:56Z

On Wed, Jul 31, 2024 at 7:25 PM Breno Leitao <leitao@debian.org> wrote:
>
> Hello Paolo,
>
> On Tue, Jul 30, 2024 at 11:38:38AM +0200, Paolo Abeni wrote:
> > Could you please benchmark such scenario before and after this patch?
>
> I've tested it on a 18-core Xeon D-2191A host, and I haven't found any
> different in either TX/RX in TCP or UDP. At the same time, I must admit
> that I have very low confidence in my tests.
>
> I run the following tests for 10x on the same machine, just changing my
> patch, and I getting the simple average of these 10 iterations. This is
> what I am doing for TCP and UDP:
>
> TCP:
> # iperf -s &
> # iperf -u -c localhost
>
> Output: 16.5 Gbits/sec
>
> UDP:
> # iperf -s -u &
> # iperf -u -c localhost
>
> Output: 1.05 Mbits/sec
>
> I don't know how to explain why UDP numbers are so low. I am happy to
> run different tests, if you have any other recommendation.

I think the iperf tool uses '-b 1' as default, which is explained in
the man page:
CLIENT SPECIFIC OPTIONS
-b, --bandwidth n[kmgKMG][,n[kmgKMG]] | n[kmgKMG]pps
set target bandwidth to n bits/sec (default 1
Mbit/sec) or n packets per sec. This may be used with TCP or UDP.
Optionally, for variable loads, use format of
mean,standard deviation

So, if you try the parameter like '-b 40MB', it will reach around
40MB/sec speed.

If I were you, I could try the following way:
1) iperf3 -s
2) iperf3 -u -c 127.0.0.1 -b 0 -l 64

Hope it can help you:)

Thanks,
Jason

>
> --breno
>