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From: Dave Taht <dave.taht@gmail.com>
To: Hal Murray <hmurray@megapathdsl.net>
Cc: bloat <bloat@lists.bufferbloat.net>
Subject: Re: [Bloat] Graph of bloat
Date: Wed, 8 Jul 2015 08:55:41 -0700	[thread overview]
Message-ID: <CAA93jw6jvDPBLhhjKZW-+0RDyRfZfDg_2deQdEe5F-BHiSKi8A@mail.gmail.com> (raw)
In-Reply-To: <20150708102317.A8994406057@ip-64-139-1-69.sjc.megapath.net>

On Wed, Jul 8, 2015 at 3:23 AM, Hal Murray <hmurray@megapathdsl.net> wrote:
> I was monitoring Google's time servers over the recent leap second.  That
> graph happened to include some good examples of bloat.
>
> http://www.megapathdsl.net/~hmurray/bloat/google-off-smear-bloat.png
>
> I have a slow DSL line with almost 4 seconds of buffering.
>
> The blobs at -20 and -15 seconds are typical of a single large download.  The
> column at -6 seconds is typical of several active connections.

That is a very interesting graph! Does ntp adjust system time backward
based on getting nearly all it's samples with well over a 1/2 second
of induced delay?

Interestingly (or disturbingly) - dnsmasq just found and fixed a crash
bug that happened when time ran backwards. I can imagine a few other
core utilities/protocols/system services that should be checked for
bad behavior in this case.

http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2015q3/009701.html


>
> --
> These are my opinions.  I hate spam.
>
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-- 
Dave Täht
worldwide bufferbloat report:
http://www.dslreports.com/speedtest/results/bufferbloat
And:
What will it take to vastly improve wifi for everyone?
https://plus.google.com/u/0/explore/makewififast

  reply	other threads:[~2015-07-08 15:55 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-08 10:23 Hal Murray
2015-07-08 15:55 ` Dave Taht [this message]
2015-07-08 16:11   ` Jan Ceuleers
2015-07-08 16:29     ` Jan Ceuleers
2015-07-08 19:09       ` Alan Jenkins
2015-07-08 16:32     ` Dave Taht
2015-07-09 10:08       ` Jan Ceuleers
2015-07-08 17:53   ` Rich Brown
2015-07-09 10:07   ` Hal Murray
2015-07-09 10:55     ` Sebastian Moeller
2015-07-09 18:27       ` Hal Murray
2015-07-09 15:08     ` Dave Taht

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