Community discussions

 
WeWiNet
Member Candidate
Member Candidate
Topic Author
Posts: 168
Joined: Thu Sep 27, 2018 4:11 pm

RB4011 "under clocking" at 533MHz / frequency scaling

Thu Aug 29, 2019 5:35 pm

How good/useful/dangerous is it to under clock RB4011 (down to 533MHz).

I use RB4011 mainly for the 10 x Geth + 5Ghz 4x4 Wifi it offers, but don't need all the CPU horse power it offers.
Now I saw the clock speed selection under ROUTERBOARD and started to reduce clock speed down to 533Mhz, hoping to safe also some power.

Two question arise:
- CPU load still shows same numbers as before, I wonder if load is measured relative to the full (normal) clock speed or relative to available MIPS (533M)?
- Any feedback / experience when using very low CPU frequency...? In theory you should only see worst case CPU being 100% if loaded, but you never know if there
are side effects...

Any feedback/knowledge out there?

Last but not least, anyone doing scripting based CPU frequency scaling???
WeWiNet

**
MTCNA
hapac2, map, hap-lite, ltap-mini, RB4011 :-) !!!
 
User avatar
sebastia
Forum Guru
Forum Guru
Posts: 1790
Joined: Tue Oct 12, 2010 3:23 am
Location: Antwerp, BE

Re: RB4011 "under clocking" at 533MHz / frequency scaling

Thu Aug 29, 2019 7:13 pm

Hey

cpu frequency settings requires a reboot to become active (part of boot configuration), so use of script would be limited.

Impact-wise, functionally it should do exactly same thing, but slower... Anything running on cpu will be impacted: routing, queuing, firewall, ...
Hardware based switching / bridging (within a single chip) should be fine as running on the switch itself.

It will run cooler, but don't expect much power reduction, as it's already a low power device.
 
WeWiNet
Member Candidate
Member Candidate
Topic Author
Posts: 168
Joined: Thu Sep 27, 2018 4:11 pm

Re: RB4011 "under clocking" at 533MHz / frequency scaling

Thu Aug 29, 2019 10:58 pm

Sebastia,

thanks for your feedback.

On RB4011 you can change clock frequency without reboot (when reading CPU info, it shows the new set frequency even without reboot).
and the message: "WARNING: cpu not running at default speed"

I don't feel RB4011 is "low power", but I will try to do some power measurements when I have time to do so to see what is makes.
WeWiNet

**
MTCNA
hapac2, map, hap-lite, ltap-mini, RB4011 :-) !!!
 
User avatar
sebastia
Forum Guru
Forum Guru
Posts: 1790
Joined: Tue Oct 12, 2010 3:23 am
Location: Antwerp, BE

Re: RB4011 "under clocking" at 533MHz / frequency scaling

Thu Aug 29, 2019 11:56 pm

busted ;-), I don't own a 4011... Good to know, thx

I meant low-power, based on actual usage: "Max power consumption 44 W"
that's not a lot

Who is online

Users browsing this forum: Google [Bot] and 66 guests