From: Eric Dumazet <eric.dumazet@gmail.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Ben Hutchings <bhutchings@solarflare.com>,
Network Development <netdev@vger.kernel.org>
Subject: Re: LRO/GRO and libpcap packet reordering
Date: Thu, 14 Mar 2013 23:54:55 +0100 [thread overview]
Message-ID: <1363301695.29475.38.camel@edumazet-glaptop> (raw)
In-Reply-To: <CALCETrUidEuaxBeDdDwGb=Dx5iGm1CK-HGWNXRUev5xoR9fnRg@mail.gmail.com>
On Thu, 2013-03-14 at 15:45 -0700, Andy Lutomirski wrote:
> Hmm. What if the GRO flow hashing was something like hash(one
> endpoint) ^ hash(the other endpoint)? (NB: I don't really know what
> I'm talking about.)
There is no hashing in GRO, but a full flow match.
What you describe has to do with multi queue capability of the NIC.
Each flow is handled by a separate RX queue, therefore by different
cpus. There is no guarantee packets are delivered 'in order' in this
case, GRO being off or on.
Of course, if GRO/LRO is on, there is an additional delay to permit
aggregation, so a big GRO/LRO packet might appear _after_ an ACK.
next prev parent reply other threads:[~2013-03-14 22:54 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-14 20:37 LRO/GRO and libpcap packet reordering Andy Lutomirski
2013-03-14 21:58 ` Ben Hutchings
2013-03-14 22:45 ` Andy Lutomirski
2013-03-14 22:54 ` Eric Dumazet [this message]
2013-03-14 22:58 ` Andy Lutomirski
2013-03-14 23:16 ` Eric Dumazet
2013-03-14 23:21 ` Eric Dumazet
2013-03-14 23:22 ` Andy Lutomirski
2013-03-14 23:01 ` Ben Hutchings
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