RPI4 clock speeds and serial port ( temperatures idle and -j4 buildworld buildkernel )

[Klaus Küchemann]

> Am 20.03.2021 um 01:53 schrieb bob prohaska <fbsd at www.zefox.net>:
> 
> Powerd does seem to affect the apparent speed of the Pi,
> and seems to make it run a bit hotter, though I've not
> paid enough attention to know by how much. Trying another
> buildworld/kernel to get a sense of average speed.
> 
> By any chance, was powerd enabled by default in the distant
> (year or so) past? Things seemed to slow down markedly after 
> then. I always thought it was due to changes in clang. 
> 

as Mark said, powerd isn’t enabled by default in releases , so the freq is @600 by default.
So 17 hours @4x600 .
with powerd enabled you should have automatically exactly 4x1500 during the complete compilation time.
sysctl dev.cpu.0.freq will definitely show the current freq.
example : using the screen tool:
1. root at generic:# sysctl dev.cpu.0.freq
dev.cpu.0.freq: 600
2.: screen
Now start ‚make -j4 xyz‘
Ctrl-a-d to detach screen
3. root at generic:# sysctl dev.cpu.0.freq
dev.cpu.0.freq: 1500

by requesting cpu-power, it is automatically scaled.
I didn`t test how powerd handles manually overclocking or sdram_freq etc., 
perhaps Mark has(or will) test that more .

K.