Re: [PATCH net-next 3/4] r8152: Add irq mitigation for RTL8157/9

Andrew Lunn
2026-05-01T12:21:20Z

> However, there is a big difference in CPU-load when running iperf3,
> especially with multiple threads:
>
> WITH the CODE saying it disables IRQ mitigation:
> $ iperf3 -c 192.168.3.1
> [ 5] 0.00-10.00 sec 10.3 GBytes 8.83 Gbits/sec
> CPU: iperf3 22.5% ksoftirqd 16.6%
>
> $ iperf3 -c 192.168.3.1 -P4
> [SUM] 0.00-10.00 sec 9.36 GBytes 8.04 Gbits/sec
> perf3: 19.3% ksoftirqd 96.7%
>
>
> WITHOUT the CODE saying it disabled IRQ mitigation:
> [ 5] 0.00-10.00 sec 10.3 GBytes 8.87 Gbits/sec
> CPU: perf3 19.7% ksoftirqd 12.5%
>
> $ iperf3 -c 192.168.3.1 -P4
> [SUM] 0.00-10.00 sec 10.3 GBytes 8.81 Gbits/sec
> CPU: iperf3 22.0% ksoftirqd 46.5%

Thanks for doing this performance testing.

> My undestanding from the first email by Michal is that the behavior with the
> ESHUTOWN is actually harmless and has been seen in the driver already for
> the RTL8153.
>
> So, my suggestion is I drop this part of the patch-series and remove the
> IRQ-mitigation code that says it disables the IRQ mitigation as performance
> is higher without that code.

Agreed.

Andrew