netdev - Re: [PATCH] net: af_packet: add af

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Message-ID: <CANn89iKpG2-+oj45SEwOggj+3j682Cgh+L7+61HF6Q0YspPikQ@mail.gmail.com>
Date: Wed, 6 Aug 2025 01:51:36 -0700
From: Eric Dumazet <edumazet@...gle.com>
To: Xin Zhao <jackzxcui1989@....com>
Cc: willemdebruijn.kernel@...il.com, davem@...emloft.net, kuba@...nel.org, 
	pabeni@...hat.com, horms@...nel.org, netdev@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: af_packet: add af_packet hrtimer mode

On Tue, Aug 5, 2025 at 10:52 PM Xin Zhao <jackzxcui1989@....com> wrote:
>
> In a system with high real-time requirements, the timeout mechanism of
> ordinary timers with jiffies granularity is insufficient to meet the
> demands for real-time performance. Meanwhile, the optimization of CPU
> usage with af_packet is quite significant. Add hrtimer mode to help
> compensate for the shortcomings in real-time performance.
>
> Signed-off-by: Xin Zhao <jackzxcui1989@....com>

I doubt we need another CONFIG option ?

Also this seems to be beneficial for HZ=100 or HZ=250 configuration,
maybe worth mentioning in the changelog.

But more importantly, I think you should explain what difference this
really makes,
in which circumstances this timer needs to fire...

If real-time is a concern, maybe using a timer to perform GC-style operation
is a no go anyway...