This is so exciting. Unfortunately they're out of stock now ! 2015-02-10 0:05 GMT+01:00 katja <katjavet...@gmail.com>:
> Using the following command to check cpu frequency on RPi model 2B: > > sudo watch -n 1 cat /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_cur_freq > > I found that RPi model 2B does frequency scaling by default (nothing > modified in /boot/config.txt). It switches between 600 and 900 MHz. > This doesn't really give substantial power saving so I wanted to > replace 'ondemand' governor with 'performance' by setting > 'force_turbo=1' in config.txt. But this caused all sorts of > instabilities, at least in combination with Pd, and I had to disable > turbo. > > So there's two things going on which Pd doesn't like: frequency > scaling and core switching. Both happen on my core2duo laptop as well, > where Pd doesn't have a problem. Anyway, pd's '-nosleep' option saves > the day. > > Now for the good news: performance gain. I compared model B+ with 2B > by running instances of Martin Brinkmann's chaosmonster1.pd > (http://www.martin-brinkmann.de/pd-patches.html) at default samplerate > and with 10 ms buffer. Model B+ can run one chaosmonster without > xruns, but not two. Model 2B can run five instances of > chaosmonster1.pd without xruns, while the GUI remains fully > responsive. This is not poor Pi as we know it, it's a different beast. > I must say that puredata 0.46-2 was compiled from Raspbian jessie > source on the Pi itself in both cases. This process uses GNU autotools > which may have set platform specific optimizations. In any case, > performance gain is much more substantial than I would expect. > Hopefully I'm not dreaming. > > Katja > > _______________________________________________ > Pd-list@lists.iem.at mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list >
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