From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@quanstro.net>
Date: Sat, 20 Feb 2016 09:20:52 -0800
To: 9fans@9fans.net
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Subject: Re: [9fans] rtl8169 gbe slow
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On Sat Feb 20 06:04:02 PST 2016, tlaronde@polynum.com wrote:
> On Sat, Feb 20, 2016 at 02:31:54PM +0100, hiro wrote:
> > what is the latency on WAN?
>
> When using traceroute, I have 42.6ms for a roundtrip
> (cf. with LAN: 0.23ms).
>
> But the very same machine, under NetBSD, with the very same ip address,
> downloads the very same file from the very same external server
> (downloads.kergis.com) in 17s, while hget(1) spends 6 minutes doing
> it.
>
> I wondered if the unsupported same chip integrated network card would
> be a problem. But disabling it via the BIOS doesn't change anything.
>
> Is there a way to trace what hget is doing/calling so that I can have a
> clue about the bottleneck? There is no transmission errors on the
> interface, so the problem is in the upper levels of TCP/IP.

yes.  i believe this was suggested before.  from the evidence, the best
guess is that you are using an old kernel with an old tcp.

the old tcp had abysmal performance starting at a latency of ~10ms.  this
was due to a flawed implementation of tcp reno.  plan 9 used to commit
the cardinal sin of tcp, and move the left edge of the window.

anyway, please update your tcp.  the debugging tools that are most
helpful with tcp are
/net/tcp/stats
/net/tcp/*/status
echo tcp>/net/log && tail -f /net/log

- erik