Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 8 Jan 2007 19:58:26 -0000
From:      "Steven Hartland" <killing@multiplay.co.uk>
To:        <freebsd-hackers@freebsd.org>, <freebsd-net@freebsd.org>
Subject:   Slow FreeBSD -> Windows performance with inflight enabled
Message-ID:  <066101c7335f$611c41e0$b3db87d4@multiplay.co.uk>

next in thread | raw e-mail | index | archive | help
I've just been looking at an issue reported by some
of our users that downloads from our one of our sites
run on FreeBSD 6.1 and Apache 1.3 where strangely
slow.

After doing some digging around I found that two remote
machines on the same network had wildly different results.
The difference being one was Windows (slow) and one was
FreeBSD 6.1 (fast).

The results where 380Kb/s download speeds on Windows vs
500Kb/s on FreeBSD. I played around and Googled to find
that this appears to caused by inflight. Disabling it
and restarting apache cures the problem.

This has been mentioned a few times in the past e.g.
http://lists.freebsd.org/pipermail/freebsd-stable/2006-February/022622.html
http://lists.freebsd.org/pipermail/freebsd-net/2005-November/008989.html

But I cant find any real conclusive results.

For reference the connection between the test machines
is initially GE on both ends but at one point goes via
DSL but is still relatively low latency the trace being:

 Host       Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. x.x.x.x  0.0%    12    0.3   0.3   0.3   0.3   0.0
 2. x.x.x.x  0.0%    12    0.4   0.4   0.4   0.4   0.0
 3. x.x.x.x  8.3%    12    1.4   1.7   1.3   3.1   0.6
 4. x.x.x.x  0.0%    11    5.5  10.1   5.5  21.6   5.9
 5. x.x.x.x  0.0%    11    7.6   6.8   6.3   7.6   0.3
 6. x.x.x.x  0.0%    11    7.7   7.2   6.7   8.1   0.4

Looking at the before and after traces using wireshark
on the windows box there are no notable changes just
an increased throughput in exchanges.

Possibly of note is that the server in question is
running a 200HZ kernel.

With the common client being Windows I'd say it would
be good to get the default improved either by disabling
inflight or changing it so that it better detects this
sort of common connection arrangement.

Does anyone have any ideas why inflight is causing such
poor performance?

    Steve


================================================
This e.mail is private and confidential between Multiplay (UK) Ltd. and the person or entity to whom it is addressed. In the event of misdirection, the recipient is prohibited from using, copying, printing or otherwise disseminating it or any information contained in it. 

In the event of misdirection, illegible or incomplete transmission please telephone +44 845 868 1337
or return the E.mail to postmaster@multiplay.co.uk.




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?066101c7335f$611c41e0$b3db87d4>