[PD] gui causing audio stutters?

Olaf Matthes olaf.matthes at gmx.de
Thu Nov 13 23:06:19 CET 2003


Matthew Nish-Lapidus schrieb:
> I'm not sure how to resolve this.. running in -rt mode used to help,
> but i'm running on os x and -rt mode doesn't exist any more.  

Can somebody please enlighten me what's up with -rt on OS X? I once
tried it (after logging in as root) and the pd-watchdog started as
expected (haven't checked the priority settings). But audio drops were
still there: Pd is _unusable_ on my G3 400MHz Pismo with 640 MB Ram, OS
X 10.2.6, internal sound or Motu 828 (Max/MSP works fine on the very
same machine) - Maybe there are less audio drops when I run Pd wih -rt
but maybe that's just what my ears expected to hear. At least the
watchdog does not kill Pd even if I have 120% CPU load reported by Pd.
So it seems there's something wrong with -rt on OS X or it isn't working
at all....

BTW, below is what I get on my machines. I tried to load as many [osc~
200] objects as possible with only one connected to dac~ to check the
sound. Shown are the number of osc~ objects where trouble starts.

Olaf

-------------------------------------------------------------------

G3 400MHz (internal audio, 44.1kHz):

- pd 0.36 w/o -rt flag: 
   - 1x osc~ - dropouts when moving windows
   - 140x osc~ - constant audio dropouts that get heavier when 
                 moving the mouse

- pd 0.36 with -rt flag:
   - 1x osc~ - dropouts when moving windows
   - 340x osc~ - constant audio dropouts that get heavier when 
                 moving the mouse


SGI Octane R12k 300MHz (internal analogue IO, 44.1kHz):

- pd 0.36 w/o -rt flag: 
   - 220x osc~ - audio dropout when moving windows

- pd 0.36 with -rt flag:
   - 500x osc~ - no audio drops but watchdog kills Pd when moving 
                 windows (92% CPU usage reported by top)


Pentium 4, 1.8GHz (Motu 828, 44.1kHz, asio driver):
- pd 0.36 (no -rt flag, of course): 
   - 248x osc~ - audio dropouts when moving windows (about 70% CPU)

- pd 0.36 set to realtime with task manager:
   - 248x osc~ - audio dropouts when moving windows (they sound a
                 bit different and the gui is slower...)





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