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>
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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.
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