[Bloat] Best practices for paced TCP on Linux?

Steinar H. Gunderson sgunderson at bigfoot.com
Fri Apr 6 17:37:25 EDT 2012


Hi,

This is only related to bloat, so bear with me if it's not 100% on-topic;
I guess the list is about the best place on the Internet to get a reasonble
answer for this anyway :-)

Long story short, I have a Linux box (running 3.2.0 or so) with a 10Gbit/sec
interface, streaming a large amount of video streams to external users,
at 1Mbit/sec, 3Mbit/sec or 5Mbit/sec (different values). Unfortunately, even
though there is no congestion in _our_ network (we have 190 Gbit/sec free!),
some users are complaining that they can't keep the stream up.

My guess is that this is because at 10Gbit/sec, we are crazy bursty, and
somewhere along the line, there will be devices doing down conversion without
enough buffers (for instance, I've seen drop behavior on Cisco 2960-S in a
very real ISP network on 10->1 Gbit/sec down conversion, and I doubt it's the
worst offender here).

Is there anything I can do about this on my end? I looked around for paced
TCP implementations, but couldn't find anything current. Can I somehow shape
each TCP stream to 10Mbit/sec or so each with a combination of SFQ and TBF?
(SFQRED?)

I'm not very well versed in tc, so anything practical would be very much
appreciated. Bonus points if we won't have to patch the kernel.

/* Steinar */
-- 
Homepage: http://www.sesse.net/



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