On Sat, Nov 18, 2017 at 5:18 AM, Pete Heist <[email protected]> wrote: > > On Nov 17, 2017, at 11:55 PM,[email protected] wrote: > > > Slotting is a crude approximation of the behaviors of shared media such > as cable, wifi, and LTE, which gather up a bunch of packets within a > varying delay window and deliver them, relative to that, nearly all at > once. > > > Nice…
Meh. It really is "crude", and I keeping kicking about ways to somehow emulate half (or less) duplex, variable rates around a mean, mcast, etc. it IS very nice to have a rate limiter that actually behaves a bit more like wifi, and I hope to also add the new ack fitering stuff to it. > > One of the things I also notice in my LAN tests is latencies for different > flows staying at more or less fixed (and different) positions relative to > the mean in flent results. Those positions, and the mean, can change with > each test run. Do you think this could result from the hashing to different > hardware queues (four in my case) changing between test runs? yes if you are using bql probably. Is it sch_mq on top? > And is it > worth trying to simulate this effect, or not really? Dunno. There are a couple ways to turn it off. > Just for info, in my case (Intel i210) the hashing is documented starting on > page 254 of the specs: > https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/i210-ethernet-controller-datasheet.pdf > (7.1.2.10.1 RSS Hash Function). For TCP/UDP it uses source and destination > addresses and ports. I suppose this could be smoothed over in testing by > using a spread of ports for the latency test. -- Dave Täht CEO, TekLibre, LLC http://www.teklibre.com Tel: 1-669-226-2619 _______________________________________________ Cake mailing list [email protected] https://lists.bufferbloat.net/listinfo/cake
