linux-kernel - Re: [PATCH net-next v4 4/4] net: gro: move L3 flush checks to tcp_gro

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Date: Tue, 26 Mar 2024 17:14:12 +0100
From: Paolo Abeni <pabeni@...hat.com>
To: Richard Gobert <richardbgobert@...il.com>, Eric Dumazet
	 <edumazet@...gle.com>
Cc: davem@...emloft.net, kuba@...nel.org, willemdebruijn.kernel@...il.com, 
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-kselftest@...r.kernel.org
Subject: Re: [PATCH net-next v4 4/4] net: gro: move L3 flush checks to
 tcp_gro_receive

Hi,

On Tue, 2024-03-26 at 16:02 +0100, Richard Gobert wrote:
> This patch is meaningful by itself - removing checks against non-relevant
> packets and making the flush/flush_id checks in a single place.

I'm personally not sure this patch is a win. The code churn is
significant. I understand this is for performance's sake, but I don't
see the benefit??? 

The changelog shows that perf reports slightly lower figures for
inet_gro_receive(). That is expected, as this patch move code out of
such functio. What about inet_gro_flush()/tcp_gro_receive() where such
code is moved?

Additionally the reported deltas is within noise level according to my
personal experience with similar tests.

I think we are better off without this patch.

Paolo