[Bloat] tiny monsters: multicast packets

[Eric Dumazet]

Le dimanche 29 mai 2011 à 11:40 -0600, Dave Taht a écrit :

>         
> 
> perf-top does not appear to have been ported to openwrt, and as cool
> as it is, I do not know if the related performance counters exist for
> mips.
> 
> it would be darn useful though.
> 
> All I know at the moment is that sirq is at 99% at the given
> workload, 
> according busybox's top.
> 
> http://www.bufferbloat.net/attachments/download/33/routertest.png
> 
> It is mildly early to point at the driver as being the issue - it
> could be the switch or something else entirely. Would iptables or qos
> rules show up in sirq?
> 

Yes, about all this stuff is run in softirq. QOS can be a problem if
high resolution kernel time services are expensive on this platform.

You could try a raw routing stuff, with no QOS / iptables, just to see
how much packets can be received/sent by this unit.

And if it stills sucks, just do an input test only, dropping packets
immediately with "iptables -I INPUT -i name -j DROP" (to check how many
packets/second can be received by the driver)