From: David Miller <davem@davemloft.net>
To: ecree@solarflare.com
Cc: herbert@gondor.apana.org.au, alexander.duyck@gmail.com,
aduyck@mirantis.com, tom@herbertland.com, jesse@kernel.org,
edumazet@google.com, netdev@vger.kernel.org
Subject: Re: [net PATCH v2 2/2] ipv4/GRO: Make GRO conform to RFC 6864
Date: Tue, 05 Apr 2016 19:45:17 -0400 (EDT) [thread overview]
Message-ID: <20160405.194517.431351466693438399.davem@davemloft.net> (raw)
In-Reply-To: <5703D4C5.9060305@solarflare.com>
From: Edward Cree <ecree@solarflare.com>
Date: Tue, 5 Apr 2016 16:07:49 +0100
> On the gripping hand, I feel like GRO+TSO is the wrong model for
> speeding up forwarding/routing workloads. Instead we should be
> looking into having lists of SKBs traverse the stack together,
> splitting the list whenever e.g. the destination changes.
"Destination" is a very complicated beast. It's not just a
destination IP address.
It's not even just a full saddr/daddr/TOS triplet.
Packets can be forwarded around based upon any key whatsoever in the
headers. Netfilter can mangle them based upon arbitrary bits in the
packet, as can the packet scheduler classifier actions.
It's therefore not profitable to try this at all, it's completely
pointless unless all the keys match up exactly.
This is why GRO _is_ the proper model to speed this stuff and do
bulk processing, because it still presents a full "packet" to all
of these layers to mangle, rewrite, route, and do whatever else
however they like.
next prev parent reply other threads:[~2016-04-05 23:45 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-04 16:27 [net PATCH v2 0/2] Fixes for GRO and GRE tunnels Alexander Duyck
2016-04-04 16:28 ` [net PATCH v2 1/2] GRE: Disable segmentation offloads w/ CSUM and we are encapsulated via FOU Alexander Duyck
2016-04-04 16:31 ` [net PATCH v2 2/2] ipv4/GRO: Make GRO conform to RFC 6864 Alexander Duyck
2016-04-05 0:38 ` subashab
2016-04-05 3:44 ` Herbert Xu
2016-04-05 4:26 ` Alexander Duyck
2016-04-05 4:32 ` Herbert Xu
2016-04-05 15:07 ` Edward Cree
2016-04-05 15:36 ` Tom Herbert
2016-04-05 17:06 ` Edward Cree
2016-04-05 17:38 ` Tom Herbert
2016-04-06 0:04 ` Marcelo Ricardo Leitner
2016-04-05 23:45 ` David Miller [this message]
2016-04-06 11:21 ` Edward Cree
2016-04-06 13:53 ` Tom Herbert
2016-04-06 14:26 ` Edward Cree
2016-04-06 15:39 ` Eric Dumazet
2016-04-06 15:55 ` Edward Cree
2016-04-06 16:03 ` Eric Dumazet
2016-04-06 15:43 ` David Miller
2016-04-06 17:42 ` Tom Herbert
2016-04-06 19:30 ` David Miller
2016-04-05 15:52 ` Alexander Duyck
2016-04-05 16:30 ` Eric Dumazet
2016-04-05 16:45 ` Alexander Duyck
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