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 <cla...@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 > > > > _______________________________________________ > Pd-list@lists.iem.at mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list _______________________________________________ Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list