[PD] multi cpu

Linium intent at club-internet.fr
Sat Mar 9 17:32:18 CET 2002

Le Samedi 9 Mars 2002 12:44, _-¯-_ a écrit :
> hi
> does anyone have experience with pd running on a dual system?


> basically, if i just start 1 pd normally, will it be using both cpus
> transparently?

Yes and no.
PD can have some multithreaded objects and externals but there are only 2 of 
them available (readsf~ and writesf~).

In the real life you have to run 2 PD if you want to share the processing 

BTW, you can use the csound~ object,  each object launchs an independant 
csound task. 
> pd -> loadmeter said: ~100%
> top says pd ~50%
> from my experience with dual machines so far, top should actually go up
> to 200% with 2 cpus on full load?

200% if you sum up all the listed threads.
100% for the maximum load of a given task using all of the power of one cpu. 

The PD loadmeter and top should say the same thing.
Probably the update time is too slow ? You can lower it in top hitting "s". 

> then there's the mosix setup, which requires some kernel patching and
> brings in the 'runon' command, but all the info i could get seems really
> outdated and applying only for up to 2.2 kernels, e.g. the SMP-HOWTO on
> linuxdoc.org seems really not up to date ..
> any hints ?

A 2.4 low latency kernel is probably a good start, but even without you can 
run 2 PD without too much trouble, unless you need read/writing to disc.

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