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Date: Thu, 9 May 2013 23:39:39 +0200
From: Hagen Paul Pfeifer <hagen@jauu.net>
To: Dave Taht <dave.taht@gmail.com>
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Cc: bloat <bloat@lists.bufferbloat.net>
Subject: Re: [Bloat] tcp loss probes in linux 3.10
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* Dave Taht | 2013-05-09 13:55:18 [-0700]:

>While this appears to make a great deal of sense
>
>http://tools.ietf.org/html/draft-dukkipati-tcpm-tcp-loss-probe-01
>
>and just landed in
>
>http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6ba8a3b19e764b6a65e4030ab0999be50c291e6c
>
>I was intrigued by several of the pieces of data that drive this stuff
>
>Measurements on Google Web servers show that approximately 70% of
>   retransmissions for Web transfers are sent after the RTO timer
>   expires, while only 30% are handled by fast recovery.  Even on
>   servers exclusively serving YouTube videos, RTO based retransmissions,
>
>96% of the timeout episodes occur without any preceding duplicate ACKs or
>other indication of losses at the sender

Btw: Nandita introduced a new MIB entry: LINUX_MIB_TCPLOSSPROBES.

$ nstat -a | grep TCPLossProbes

will show fired probes.



Hagen