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

Sebastian Moeller moeller0 at gmx.de
Fri Jun 26 10:17:38 EDT 2015

Hi Mikael,

On Jun 26, 2015, at 14:26 , Mikael Abrahamsson <swmike at swm.pp.se> wrote:

> On Fri, 26 Jun 2015, Sebastian Moeller wrote:
>> Thanks for the tests, now I know what router to try next (the edgerouterX, which I had eyed as a replacement for the shaper in the wndr3700 tops out at 130K packets per second and hence will not really work that well for a 100/40 Mbps link).
> I did some more tests and it seems with SQM at 500 megabit/s I start to lose packets at around 250-300k PPS. At these speeds, the rrul_be test is "only" 85k PPS at 500 megabit/s bidirectional with large packets.

	Ah, that sounds like there 1200ac is a practical solution today; at 500Mbps there are 500^3/(64*8) = 244  Kpps at the smallest size (since the wire is at 1000 Mbps I think we should and can ignore inter frame gap and preamble, SQM certainly ignores them) so it looks like the router is really close to the theoretical maximum, and with larger packets things get way more relaxed (500^3/(1518*8) = 10 Kpps). Pretty decent for a router using no proprietary offload features.

> Also, I have an Edgerouter ER-5, but as soon as it does CPU based forwarding it's really weak, easily under 100 megabit/s even with large packets. OpenVPN without encryption is less than 20 megabit/s.

	Ah, interesting, so neither the affordable edge router lite nor the (similar) ER-5 will cut it unless the offloads are used; I think the newer edgerouterX is rated for slightly higher speeds without offloads, but not nearly close to what your 1200ac does...

> Btw, the WRT1200AC is now becoming more widely available and it's 150 EUR incl 25% VAT and shipping here in Sweden now.

	In Germany it still retails for around 200EUR with the cheapest offer at 180EUR (but that is an outlier); guess I should visit Sweden then ;)

> Btw, I tried WNDR3800 setting it to 100/100 SQM.

	Yeah, not pretty, huh?

> 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?

	Interesting observation, no idea, but intrigued ;)

Best Regards

> -- 
> Mikael Abrahamsson    email: swmike at swm.pp.se

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