From: Rick Jones <rick.jones2@hp.com>
To: David Miller <davem@davemloft.net>
Cc: andi@firstfloor.org, netdev@vger.kernel.org
Subject: Re: small RPS cache for fragments?
Date: Tue, 17 May 2011 15:42:48 -0700 [thread overview]
Message-ID: <1305672168.8149.966.camel@tardy> (raw)
In-Reply-To: <20110517.175044.2057517197524794568.davem@davemloft.net>
On Tue, 2011-05-17 at 17:50 -0400, David Miller wrote:
> From: Andi Kleen <andi@firstfloor.org>
> Date: Tue, 17 May 2011 14:48:28 -0700
>
> > David Miller <davem@davemloft.net> writes:
> >
> >> Guys we can't time out fragments if we are not the final
> >> destination.
> >
> > If you're not the final destination you should never even
> > try to reassemble them?
> >
> > I'm probably missing something...
>
> We're discussing the idea to do the defragmentation first
> so we can choose the flow properly and steer the packet
> to the correct cpu.
>
> This also would allos each fragmented packet to traverse the
> stack only once (one route lookup etc.) instead of once per
> fragment.
>
> Please read the rest of this thread, we have discussed this
> and now I'm repeating information solely for your benefit.
Well, I should probably be beaten with that stick too because I wasn't
thinking about forwarding, only being the destination system when I
broached the suggestion of doing RFS after reassembly. I can see where
one *might* be able to do limited RPS when forwarding, but I didn't know
that RFS had been extended to forwarding.
Now though I see why you were rightfully concerned about timeouts -
given all the concerns about added latency from bufferbloat, I wouldn't
think that an additional 10 or perhaps even 1ms timeout on a reassembly
attempt to get the layer four header when forwarding would sit well with
folks - they will expect the fragments to flow through without
additional delay.
rick jones
next prev parent reply other threads:[~2011-05-17 22:42 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-17 18:33 small RPS cache for fragments? David Miller
2011-05-17 20:02 ` Tom Herbert
2011-05-17 20:17 ` Rick Jones
2011-05-17 20:41 ` Rick Jones
2011-05-17 20:49 ` David Miller
2011-05-17 21:00 ` Eric Dumazet
2011-05-17 21:10 ` David Miller
2011-05-17 21:13 ` Rick Jones
2011-05-17 21:13 ` Ben Hutchings
2011-05-17 21:26 ` David Miller
2011-05-17 21:40 ` Rick Jones
2011-05-17 21:27 ` Eric Dumazet
2011-05-17 21:11 ` Rick Jones
2011-05-17 21:11 ` Ben Hutchings
2011-05-17 21:27 ` Tom Herbert
2011-05-17 21:28 ` David Miller
2011-05-17 23:59 ` Changli Gao
2011-05-18 6:37 ` David Miller
2011-05-17 20:14 ` Eric Dumazet
2011-05-17 20:47 ` David Miller
2011-05-17 21:44 ` Andi Kleen
2011-05-17 21:52 ` Eric Dumazet
2011-05-17 22:03 ` Andi Kleen
2011-05-17 21:44 ` David Miller
2011-05-17 21:48 ` Andi Kleen
2011-05-17 21:50 ` David Miller
2011-05-17 22:06 ` Andi Kleen
2011-05-17 22:42 ` Rick Jones [this message]
2011-05-24 20:01 ` David Miller
2011-05-24 21:38 ` Rick Jones
2011-06-04 20:29 ` David Miller
2011-06-06 17:08 ` Rick Jones
2011-06-06 17:15 ` Eric Dumazet
2011-06-06 18:06 ` Rick Jones
2011-06-06 19:23 ` David Miller
2011-06-06 19:22 ` David Miller
2011-06-06 20:05 ` Rick Jones
2011-06-06 21:06 ` Jay Vosburgh
2011-06-06 21:40 ` David Miller
2011-06-06 22:49 ` Chris Friesen
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