Cake bandwidth configuration

[networkplumber]

I see a bug when configuring upload/download bandwidth QoS (with Cake in 386.2_6)

# tc qdisc show
qdisc cake 8003: dev eth0 root refcnt 2 bandwidth 10240Kbit diffserv3 dual-srchost nat nowash no-ack-filter split-gso rtt 100ms noatm overhead 18 mpu 64
qdisc cake 8004: dev ifb4eth0 root refcnt 2 bandwidth 307200Kbit besteffort dual-dsthost nat wash ingress no-ack-filter split-gso rtt 100ms noatm overhead 18 mpu 64

This is wrong. In communications K = 1000 and M = 1000000 (SI units) in storage and other places K = 1024 (IEC units).
The iproute2 commands get this right, looks like somewhere in the GUI to qdisc scripts somewhere is using wrong multiplier.

 

[dave14305]

Yes, this is a discrepancy by Asus.

CakeQOS - CakeQoS-Merlin v2.0.0 alpha

spdMerlin.log Apr 14 13:40:56 RT-AC86U spdMerlin: Setting QoS Upload Speed to 18106 Kbps (was 19418 Kbps) Apr 14 14:10:01 RT-AC86U spdMerlin: Starting speedtest using using auto-selected server for WAN interface Apr 14 14:10:29 RT-AC86U spdMerlin: Speedtest results - Download: 131.77 Mbps (data...

www.snbforums.com

 

[pdc]

Does this mean when we enter e.g. 100 Mbps in the QoS configuration, we are actually configuring 100 x 2^20 bps(Mebibits/sec), which is actually 105 x 10^6 bps(Megabits/sec)? Is this why the recommendation to use 95% of speedtest? Or should we be using 95% of the 95% (->90%) to compensate for mebi/megabits?

 

[dave14305]

When you enter 100 Mb/s in the QoS page, it’s stored in nvram as 102400 kbps. The tc interface interprets it as 102400 kilobits (not kibibits). So I think you’re only overstating by 2.4%. This is all unrelated (AFAIK) to the 95% recommendation.

Being ultra-nerdy, I manually update nvram with my adjusted kilobit values. It displays oddly in the GUI, but I know the bandwidth is where I want it, plus I personally spend a lot of time looking at tc output so the rounder Mbits are easier to glance at.

 

[pdc]

Thanks Dave! Ultra-nerds represent! (My friends think I am an ultra-nerd for running custom firmware on my router, how little they know of nerdom )

 

[heysoundude]

Thanks Dave! Ultra-nerds represent! (My friends think I am an ultra-nerd for running custom firmware on my router, how little they know of nerdom )

they might change their tune after using your network for a while, with local DNS caching, ad-blocking...

To the original query, I just put in the 7-day Avg numbers from spdMerlin and call it a day. The graphs are populating within a percent or two of my subscribed rates (and in higher than, on the UL side), and data flows nicely in both directions. Bufferbloat is A/A+

 

[networkplumber]

Iproute already supports configuration with iec units which seems to be what Asus wants.
Assuming you have real iproute2 not the busybox version.