Re: [Cerowrt-devel] performance numbers from WRT1200AC (Re: Latest build test - new sqm-scripts seem to work; "cake overhead 40" didn't)

[Sebastian Moeller <moeller0@gmx.de>]

HI Mikael,


On Jun 26, 2015, at 16:49 , Mikael Abrahamsson <swmike@swm.pp.se> wrote:

> On Fri, 26 Jun 2015, Mikael Abrahamsson wrote:
> 
>> Btw, I tried WNDR3800 setting it to 100/100 SQM. It seems to max out around 25-30k PPS, but the difference is that when the CPU is full, it seems to delay/ECN-mark packets because there are no packets lost. When the WRT1200AC runs out of CPU it starts dropping packets. I always have 0 packets lost with the WNDR3800 when doing iperf3 testing. I found this difference interesting, wonder where in the forwarding path the WRT1200AC loses packets?
> 
> I checked again, and my WDR4900 with same setup doesn't lose packets either. Even at 99% sirq, no packets are lost.

	Tangent: What is the shaper rate the wdr4900 can push with sqm-scripts? (Before your 1200ac results the ppc-soc in the wdr4900 looked like the finest little router platform in the last years, too bad it was ignored by the mass market...)

> 
> WRT1200AC starts to lose packets at 500 megabit/s SQM around MSS 300 and lower. If I turn off gso, tso and gro, I have to go to MSS 600 and above to avoid packet loss.

	So the offloads buy roughly a doubling of the achievable packet rate, not bad, but as your results show also knot essential.


Best Regards
	Sebastian

> 
> Does flent check for packet loss at all? Perhaps it's something to look into, because with ECN we really don't want to see any packets lost and this might be good to include test results for.
> 
> -- 
> Mikael Abrahamsson    email: swmike@swm.pp.se