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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Rick Jones <rick.jones2@hp.com>
Cc: Simon Horman <horms@verge.net.au>, netdev@vger.kernel.org
Subject: Re: Bonding, GRO and tcp_reordering
Date: Tue, 30 Nov 2010 19:14:15 +0100	[thread overview]
Message-ID: <1291140855.2904.148.camel@edumazet-laptop> (raw)
In-Reply-To: <4CF53AB2.60209@hp.com>

Le mardi 30 novembre 2010 à 09:56 -0800, Rick Jones a écrit :

> Short of packet traces, taking snapshots of netstat statistics before and after 
> each netperf run might be goodness - you can look at things like ratio of ACKs 
> to data segments/bytes and such.  LRO/GRO can have a non-trivial effect on the 
> number of ACKs, and ACKs are what matter for fast retransmit.
> 
> netstat -s > before
> netperf ...
> netstat -s > after
> beforeafter before after > delta
> 
> where beforeafter comes (for now, the site will have to go away before long as 
> the campus on which it is located has been sold) 
> ftp://ftp.cup.hp.com/dist/networking/tools/  and will subtract before from after.
> 
> happy benchmarking,

Yes indeed. With fast enough medium (or small MTUS), we can enter in a
backlog processing problem {filling huge receive queues}, as seen on
loopback lately...

netstat -s can show some receive queue overrun in this case.

    TCPBacklogDrop: xxx




  reply	other threads:[~2010-11-30 18:14 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-30 13:55 Bonding, GRO and tcp_reordering Simon Horman
2010-11-30 15:42 ` Ben Hutchings
2010-11-30 16:04   ` Eric Dumazet
2010-12-01  4:34     ` Simon Horman
2010-12-01  4:47       ` Eric Dumazet
2010-12-02  6:39         ` Simon Horman
2010-12-03 13:38       ` Simon Horman
2010-12-01  4:31   ` Simon Horman
2010-11-30 17:56 ` Rick Jones
2010-11-30 18:14   ` Eric Dumazet [this message]
2010-12-01  4:30   ` Simon Horman
2010-12-01 19:42     ` Rick Jones

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