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Date: Tue, 12 Mar 2024 16:38:02 +0100
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Subject: Re: [PATCH net-next 0/4] net: route: improve route hinting
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To: David Ahern <dsahern@kernel.org>, davem@davemloft.net,
 edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, willemb@google.com
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20240307171202.232684-1-leone4fernando@gmail.com>
 <9ce73c04-ee8f-4aa5-ab15-c31dbe409401@kernel.org>
From: Leone Fernando <leone4fernando@gmail.com>
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David Ahern wrote:
> I have looked at all of the sets sent. I can not convince myself this is
> a good idea, but at the same time I do not have constructive feedback on
> why it is not acceptable. The gains are modest at best.
> 

Thanks for the comment.

I believe an improvement of 5-8% in PPS is significant. 
Note that the cache is per-cpu (e.g., for a machine with 10 CPUs, the improvement
affects 10X the conns mentioned).

Could you please provide more information about what you don't like
in the patch?

Some possible issues I can think of:
- Do you think the improvement is not affecting the common case?
In this case, it can be solved by tweaking the cache parameters.

- In case performance degradation for some # of conns is problematic - we can
find ways to reduce it. For example, the degradation for 1 connection can
probably be solved by keeping the route hints.

Leone