On Fri, May 6, 2016 at 12:29 AM, Kevin Darbyshire-Bryant <[email protected]> wrote: > Hi All, > > My brain woke up with this idea rattling around in it this > morning...obviously the subconscious has been busy. So here it is: > > Is there any way to use the egress drop signalling at ingress time to drop > stuff before it gets into the queue so then we don't have to drop it at > egress? > > Something like: At enqueue if we've a matching flow check to see if that > flow had been in egress 'fast dropping' state *and* know how much data in > terms of time it had to fast drop to get the queue back under the nominal > time threshold. If say it had to drop 10ms worth of packets to get back to > the nominal 5ms threshold then it dropped 67% of the packets/data. I'd like > to think of that as an 'unresponsive flow'...hence could it be possible to > use that information at ingress time and in essence drop (some? 66%?) of > them there, we can also signal congestion to the stack at that point to > (cake already does this signalling when getting to its buffer size limit) > > > Probably a very silly idea.
No, actualy, I'd been thinking about the same thing myself for days. :) I've always wanted a way to notify userspace that I was dropping (the heck out of) something on egress to try and stuff it up on ingress, or do something more intelligent like re-route the traffic elsewhere. There was a lot of talk about adding the ability to drop stuff really fast in the rx ring recently using the jit BPF stuff. I was at a meeting where tom herbert talked about that, and I confess, extremely dubious. Then... well, I see lots of drops on ingress already I don't want, the udp flooding episode made me go look harder at whole system behavior... and I can't find the lwn article about it. > > -- > Thanks, > > [email protected] > M: +44 7947 355344 H: +44 1256 478597 > > > _______________________________________________ > Cake mailing list > [email protected] > https://lists.bufferbloat.net/listinfo/cake > -- Dave Täht Let's go make home routers and wifi faster! With better software! http://blog.cerowrt.org _______________________________________________ Cake mailing list [email protected] https://lists.bufferbloat.net/listinfo/cake
