[PD] new raspberries

[katja]

Claude, thanks for the hint. My /boot/config.txt shows no special
settings, so I guess the CPU is at a fixed frequency. It says that
'700 MHz is the default' (while model 2B should be at 900 MHz). Seems
I downloaded the 'newest' Raspbian too early (the day after model 2B's
release)... Will try again.

Katja

On Fri, Feb 6, 2015 at 10:50 PM, Claude Heiland-Allen
<claude at mathr.co.uk> wrote:
> I've not got any version of the rpi, but maybe it's scaling down the clock
> frequency of unused cores, which then takes some time to spin up to full
> speed when a task is moved by the kernel?
>
> I also had issues on amd64 desktop and core2duo laptop with pd -rt not being
> taken into account by the kernel ondemand cpu speed governor, or some other
> issue perhaps, whereby the cpu speed would stay at ~800MHz even though it
> really needed to be higher to reduce xruns etc..  pd -nrt would scale up the
> cpu speed correctly.
>
>
> On my quad-core amd64 desktop I run this before realtime work (or nrt
> benchmarking) to set all cores to maximum speed (with the 'performance'
> governor):
>
> for c in 0 1 2 3 ; do sudo cpufreq-set -c $c -g performance ; done
>
> Then when I want to reduce fan noise / heat etc and I'm not doing much
> intensive, I reset to the default 'ondemand' governor:
>
> for c in 0 1 2 3 ; do sudo cpufreq-set -c $c -g ondemand ; done
>
>
> Might also be worth looking into setting scheduler cpu core affinity for pd,
> jackd, pd-gui, ...  but I don't know how to do that.
>
>
> Claude
>
> On 06/02/15 21:38, katja wrote:
>>
>> Aplay can play a .wav file without trouble, so it is not a general
>> problem with the audio hardware or drivers on Pi 2b.
>>
>> I installed command htop to see CPU load per core. It's interesting,
>> the load switches from one core to another, and sometimes they all
>> seem to be almost idle even with a heavy Pd patch running.
>
>
> --
> http://mathr.co.uk
>
>
>
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