From mboxrd@z Thu Jan  1 00:00:00 1970
From: Steffen Klassert <steffen.klassert@secunet.com>
Subject: Re: Big performance loss from 3.4.63 to 3.10.13 when routing ipv4
Date: Wed, 23 Oct 2013 14:26:00 +0200
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Cc: Wolfgang Walter <linux@stwm.de>,
	David Miller <davem@davemloft.net>, hannes@stressinduktion.org,
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To: Eric Dumazet <eric.dumazet@gmail.com>
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On Wed, Oct 23, 2013 at 05:00:01AM -0700, Eric Dumazet wrote:
> On Wed, 2013-10-23 at 13:33 +0200, Wolfgang Walter wrote:
> 
> > I don't know what this value actually means. But on 3.4.x it is much higher. 
> > On a machine with 512MB ram it is 32768, on a machine with 1GB ram it is 
> > 262144 and with 16GB ram it is 4194304.
> > 
> 
> Such huge values should not be needed. We should have at most one dst
> per packet in flight.

We have one cache entry for each packet flow we have already seen.
So a static value should be not too high, because remote entities
can control how many cache entries we have, similar to the routing
cache.