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Re: network queue lengths
>>>>> "David" == David Young <dyoung%pobox.com@localhost> writes:
David> If a NetBSD box is the Internet gateway for several 10-,
David> 100-, or 1000-megabit clients, and the clients share a 1-,
David> 2-, or 3-megabit Internet pipe, it is easy for some outbound
David> stream to fill both the Tx ring (max 64 packets) and the
Hmm. maybe this explains the problems on my home network.... almost
full /25 of (mostly virtual) hosts behind a 4M/800K pipe.
David> Now, suppose that we shorten the interface queue, or else we
David> "shape" traffic using ALTQ. Outbound traffic nevertheless
David> spends 1/4 to 3/4 second on the Tx ring, which may defeat
David> ALTQ prioritization in some instances.
David> This is getting a bit long, so I am going to hastily draw
David> some conclusions. Please tell me if I am way off base:
David> 1 in order for ALTQ to be really effective at controlling
David> latency for delay-sensitive traffic, it has to feed a very
David> short Tx ring
Can we do this dynamically in some way? Does WRED help here?
David> 2 maximum queue/ring lengths in NetBSD are tuned for very
David> high-speed networks, now; the maximums should adapt to hold
David> down the expected delay while absorbing momentary overflows.
I would be happy to tell ifconfig some value, since it's not the link
speed that counts...
] Y'avait une poule de jammé dans l'muffler!!!!!!!!! | firewalls [
] Michael Richardson, Sandelman Software Works, Ottawa, ON |net architect[
] mcr%sandelman.ottawa.on.ca@localhost http://www.sandelman.ottawa.on.ca/
] panic("Just another Debian GNU/Linux using, kernel hacking, security guy"); [
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