netdev - Re: Bonding, GRO and tcp

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1291140855.2904.148.camel@edumazet-laptop>
Date:	Tue, 30 Nov 2010 19:14:15 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Rick Jones <rick.jones2@...com>
Cc:	Simon Horman <horms@...ge.net.au>, netdev@...r.kernel.org
Subject: Re: Bonding, GRO and tcp_reordering

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



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html