RE: r8169: Discussion on implementing RSS support for r8169

[Javen <javen_xu@realsil.com.cn>]

>On 19.03.2026 09:56, Javen wrote:
>> Hi, Heiner
>>
>> We are now planning to implement RSS support on r8169 driver. This will
>require significant changes to the existing driver architecture, so we want to
>discuss it with you.
>>
>Thanks for the question.
>I also once considered this, but decided against it, as I didn't see enough
>benefit justifying the significantly increased complexity of the driver. Even
>with a N100-based mini-pc I can easily saturate a 2.5Gbps link with the driver
>as-is.
>Any specific reason why you consider adding RSS support? Would be good to
>see a performance comparison as basis for a decision on for which chip
>versions RSS may provide a significant benefit.
>

The primary beneft of adding rss here is to reduce cpu load per core.

Since I currently only have one RTL8111ep and one RTL8127, I'm going to do a simple test.

Based on my iperf test from RTL8111ep to RTL8127:
	1. With rss: cpu load is distributed across 4 cores(1% ~ 2% each)
	2. Without rss: cpu load is concentrated on a single core(7% ~ 8%)

If test from RTL8127 to RTL8127, especially on platforms with weaker cpu, disabling rss will easily lead to cpu overload. 
That's the main reason we consider adding rss support for RTL8127.

I will show the result from RTL8127 to RTL8127 when I submit rss patch.

Thanks,
Javen Xu

>> Based on our vendor driver which can be fetched from Realtek, the key
>modifications will include:
>>
>>       1. Enable msix and updating the irq allocation mechanism
>>       2. Support multiple rx/tx queues
>>       3. Register multiple napi and update new interrupt mapping(isr/imr) for
>multi-queue
>>       4. Implement rx msix poll and rx interrupt function
>>       5. Implement ethtool callbacks for rss configuration
>>
>> Should we submit the changes above separately or submit them all at once?
>Or do you have any other suggestions?
>>
>As Andrew already said, please submit the patches in smaller, reviewable,
>chunks.
>Best tagged as RFC.
>
>> We want to align with you on the development and submission approach.
>>
>> Best regards,
>>
>> Javen Xu
>
>Heiner