Wow. This is getting interesting again ! Thank you Katja for purchasing and testing the new version so quickly.
Pierre. 2015-02-07 15:22 GMT+01:00 katja <[email protected]>: > 10 ms buffer in audio settings was tested OK for this setup: > > Raspberry Pi model 2B > Raspbian wheezy, latest image from raspberrypi.org > LXDE desktop running > iMic USB audio interface, 2 in 2 out > puredata 0.46-2 built from Raspbian jessie source on RPi model 2B > pd started with option -nosleep, and running 'PicoJockey' > > PicoJockey is a live sampling tool with effects. I've been using it as > a Raspberry Pi test since the first 256 MB model B, for which it was > too difficult, considering the USB troubles at the time. PicoJockey > can be found here compiled on single core Raspi but the build works > for model 2B too: http://www.katjaas.nl/slicejockey/slicejockey.html > (page bottom). On model B+ I used to run PicoJockey at half the > default sample rate to save CPU time, but with model 2B it can run at > default sample rate while leaving some CPU headroom. PicoJockey's GUI > controls are pretty CPU intensive but that's where the extra cores are > useful. > > Results are quite promising and there may be options for optimization, > like compiling Pd with NEON instructions enabled (if gcc can do that). > > Katja > > On Sat, Feb 7, 2015 at 1:45 PM, Pierre Massat <[email protected]> wrote: > > Dear Katja, > > > > Could you please tell us what buffer size you're using in Pd ? Can you > get > > lower than 16 ms without dropouts with a reasonable patch with both adc > and > > dac ? > > > > Thanks in advance, > > > > Pierre. > > > > 2015-02-07 10:39 GMT+01:00 katja <[email protected]>: > >> > >> On Fri, Feb 6, 2015 at 11:56 PM, Miller Puckette <[email protected]> wrote: > >> > Also try running "pd -nosleep", which sometimes persuades kernels to > >> > schedule the process differently :) > >> > >> Indeed, "pd -nosleep" does the magic. Command htop shows hat the > >> kernel has 100% CPU time reserved on one core (fixed per session) for > >> pd -nosleep. Pd-gui runs on one of the other cores, alternating. The > >> audio is fine with no dropouts. > >> > >> It is possible to start two instances of pd -nosleep, and get a core > >> reserved for each. The second instance finds the alsa device busy of > >> course, and this makes no sense in practice. Maybe the [pd~] object > >> can profit from the multicore processor. > >> > >> I've checked current draw with the setup: Raspberry Pi + USB keyboard > >> + USB mouse + USB audio interface (iMic) together consume ~400 mA with > >> only the desktop running, and ~450 mA with pd -nosleep running idle or > >> with a CPU intensive patch. This indicates there is some frequency > >> scaling going on after all. I'll look into that again when there's > >> more info about the new Pi's config defaults and options. > >> > >> Katja > >> > >> _______________________________________________ > >> [email protected] mailing list > >> UNSUBSCRIBE and account-management -> > >> http://lists.puredata.info/listinfo/pd-list > > > > >
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