From: Dave Taht <dave.taht@gmail.com>
To: Hagen Paul Pfeifer <hagen@jauu.net>
Cc: bloat <bloat@lists.bufferbloat.net>
Subject: Re: [Bloat] tcp loss probes in linux 3.10
Date: Thu, 9 May 2013 16:01:05 -0700 [thread overview]
Message-ID: <CAA93jw4jizhh2643eNobO-o5o2hbu8c=rxg=ZAZ9y6Dm-nw6bA@mail.gmail.com> (raw)
In-Reply-To: <20130509213939.GB4170@virgo.local>
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On Thu, May 9, 2013 at 2:39 PM, Hagen Paul Pfeifer <hagen@jauu.net> wrote:
> * 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.
>
>
>
I have to admit that the 96% figure strongly suggests some degree of
bufferbloat in the tested mix here. I am curious however as to what other
causes there might be, ranging from tcp bugs to glitches in the matrix?
>
> Hagen
>
>
--
Dave Täht
Fixing bufferbloat with cerowrt:
http://www.teklibre.com/cerowrt/subscribe.html
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next prev parent reply other threads:[~2013-05-09 23:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-09 20:55 Dave Taht
2013-05-09 21:39 ` Hagen Paul Pfeifer
2013-05-09 23:01 ` Dave Taht [this message]
2013-05-09 23:43 ` Jonathan Morton
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