From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: netdev@vger.kernel.org
Subject: Re: state of rtcache removal...
Date: Wed, 16 Feb 2011 22:39:32 -0800 (PST) [thread overview]
Message-ID: <20110216.223932.112610567.davem@davemloft.net> (raw)
In-Reply-To: <1297923915.2645.24.camel@edumazet-laptop>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 17 Feb 2011 07:25:15 +0100
> Thanks David for this work in progress.
It was my pleasure :-)
> If I remember my works in last October/November, I also know fib_hash
> was a bit faster than fib_trie (around 20%)...
Right, if table is small hash can be faster.
I just wrote a hack that puts fib_lookup() results into the the
flow cache, and hooked it only into the one fib_lookup() call
that happens in ip_route_output_slow().
This pointed out another costly thing we do when resolving output
routes. If the flow key's source is not INADDR_ANY, we validate the
source address is our's by doing a fib table lookup in the local
table, with the address in the flow key's destination field.
So even on output we were doing 3 fib lookups :-/
Therefore, the flow cache hack gets rid of 2 of those 3.
prev parent reply other threads:[~2011-02-17 6:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-17 0:08 state of rtcache removal David Miller
2011-02-17 2:59 ` Tom Herbert
2011-02-17 3:27 ` David Miller
2011-02-17 6:25 ` Eric Dumazet
2011-02-17 6:39 ` David Miller [this message]
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