netdev - Re: [Question] ixgbe：Mechanism of RSS

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Message-ID: <0d625c8b-f1e0-4562-aee0-b4cbc8fc5737@shopee.com>
Date: Thu, 9 Jan 2025 11:26:52 +0800
From: Haifeng Xu <haifeng.xu@...pee.com>
To: Tony Nguyen <anthony.l.nguyen@...el.com>,
 Edward Cree <ecree.xilinx@...il.com>, Eric Dumazet <edumazet@...gle.com>,
 Aleksandr Loktionov <aleksandr.loktionov@...el.com>,
 "Kwapulinski, Piotr" <piotr.kwapulinski@...el.com>
Cc: Przemek Kitszel <przemyslaw.kitszel@...el.com>,
 "David S. Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>, linux-kernel@...r.kernel.org,
 netdev@...r.kernel.org, intel-wired-lan@...ts.osuosl.org
Subject: Re: [Question] ixgbe：Mechanism of RSS

On 2025/1/9 05:06, Tony Nguyen wrote:
> 
> 
> On 1/7/2025 7:36 PM, Haifeng Xu wrote:
>>
>>
>> On 2025/1/8 01:16, Tony Nguyen wrote:
> 
> ...
> 
>>>
>>> What's your ntuple filter setting? If it's off, I suspect it may be the Flow Director ATR (Application Targeting Routing) feature which will utilize all queues. I believe if you turn on ntuple filters this will turn that feature off.
>>
>> Yes, our ntuple filter setting is off. After turning on the ntuple filters, I compare the delta of recieved packets,
>> only 0~15 rx rings are non-zero, other rx rings are zero.
>>
>> If we want to spread the packets across 0~62, how can we tune the NIC setting?
>> we have enabled 63 rx queues, irq_affinity and rx-flow-hash, but the 0~15 cpu
>> received more packets than others.
> 
> As Jakub mentioned earlier, HW RSS is only supported on this device for 16 queues. ATR will steer bi-directional traffic to utilize additional queues, however, once its exhausted it will fallback to RSS, which is why CPUs 0-15 are receiving more traffic than the others. I'm not aware of a way to evenly spread the traffic beyond the 16 HW supported RSS queues for this device.

Ok, thanks!

> 
> Thanks,
> Tony
> 
>> Thanks!
> 
>