RPi and powerd, was: Re: RPI4 clock speeds and serial port ( temperatures idle and -j4 buildworld buildkernel )

[bob prohaska]

On Tue, Mar 23, 2021 at 02:38:25PM -0700, Mark Millard wrote:
> [This did not get sent when I wrote it. So sending way late.]
> 
> On 2021-Mar-21, at 11:13, bob prohaska <fbsd at www.zefox.net> wrote:
> 
> > On Sat, Mar 20, 2021 at 09:20:36PM -0700, Mark Millard wrote:
> >> 
> >> You are getting the vast majority of the time
> >> benefit from powerd use compared to my build
> >> context (based on the world build times). Avoiding
> >> building to allow compiling non-arm could cut
> >> your time noticeably, possibly around 30 minutes
> >> for world.
> >> 
> > 
> > Half an hour I can wait 8-) More likely I'll botch the changes.
> > 
> > After trying powerd on the Pi4 with success it was applied
> > to Pi3 and Pi2. Powerd seemed to work well on the Pi3, but
> 
> 
> > the Pi2 v1.1 stalled consistently in the building libraries
> > phase. The stall was unresponsive to the debugger escape.
> > After power-cycling and disabling powerd, the Pi2 picked
> > up where it left off. Not sure if this is a property of 
> > powerd or an artifact of my setup on the Pi2, being
> > 14.0-CURRENT FreeBSD 14.0-CURRENT #13 main-f5e930b369:
> > executing
> > make -j4 -DWITH_META_MODE  buildworld 
> 
That problem seems to have gone away, at least for now. Once
the system updated it seemed to run buildworld successfully
with powerd turned on.
 
> It might be that if you set the speed in /etc/sysctl.conf
> instead of using powerd (so the arm running at a constant
> rate), that the problem would repeat on the RPi2.
>
That sounds like it might help distinguish between a problem
with my setup and a problem with powerd. If both sysctl
acceleration and powerd acceleration cause a hang, it isn't
powerd's fault.

> Were you monitoring temperature on the RPi2? Voltage?
>
 
Temperature, casually, 55-60C, room below 20C. Voltage,
not at all. Stick-on heat sinks but no fan.

I'll simply leave powerd enabled and wait to see if the
trouble comes back. 

Thanks for writing!

bob prohaska