linux-kernel - Re: [RFC v2] net/core: add optional threading for rps backlog processing

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Message-ID: <acaf1607-412d-3142-1465-8d8439520228@nbd.name>
Date:   Fri, 17 Feb 2023 13:35:06 +0100
From:   Felix Fietkau <nbd@....name>
To:     Eric Dumazet <edumazet@...gle.com>
Cc:     netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>, linux-kernel@...r.kernel.org
Subject: Re: [RFC v2] net/core: add optional threading for rps backlog
 processing

On 17.02.23 13:23, Eric Dumazet wrote:
> On Fri, Feb 17, 2023 at 11:06 AM Felix Fietkau <nbd@....name> wrote:
>>
>> When dealing with few flows or an imbalance on CPU utilization, static RPS
>> CPU assignment can be too inflexible. Add support for enabling threaded NAPI
>> for RPS backlog processing in order to allow the scheduler to better balance
>> processing. This helps better spread the load across idle CPUs.
>>
>> Signed-off-by: Felix Fietkau <nbd@....name>
>> ---
>>
>> RFC v2:
>>  - fix rebase error in rps locking
> 
> Why only deal with RPS ?
> 
> It seems you propose the sofnet_data backlog be processed by a thread,
> instead than from softirq ?
Right. I originally wanted to mainly improve RPS, but my patch does 
cover backlog in general. I will update the description in the next 
version. Does the approach in general make sense to you?

Thanks,

- Felix