On 02/23/2014 07:37 AM, Dan Wilcox wrote:
On Feb 23, 2014, at 2:11 AM, Jonathan Wilkes <[email protected]> wrote:
Do you have an example of a patch that suffers from Pd's current
single-threaded implementation that would be measurably improved by using a
multi-threaded approach?
Ask any of the people who have to run two instances of Pd in order to have both
GEM and audio without dropouts. And this is in 2014 with modern computers
orders of magnitude more capable than when Pd was first designed.
This is probably naive, but wouldn't it suffice to have an object that
does automatically what the user is forced to do manually atm?
Manual -- user opens a Pd instance for GEM and a separate Pd instance
for audio
Auto -- user creates an object [foo-audio-magic somepatch.pd] which
automatically fires up a separate instance-- _not_ a child of the
first-- for the audio.
Also, what is the metric to use here?
Mmm open a larger patch with audio running, momentary dropouts.
How do you know that's due to Pd's single-threadedness, and not some
CPU-hogging object, or a poorly optimized object chain, or Pd doing GUI
calculations in the core thread as well as tk's thread?
Also, this is perhaps better to ask a beginner trying to pickup PD after starting with Max MSP,
they may not give you "meaningful metrics" but their impression may be along the lines of
"not only does this program look old, but it keeps clicking when I'm dragging things
around". Etc etc
That particular problem is due directly to *_getrect calls in a patch
with lots of objects (and possibly a bunch of *_click calls if hovering
over an object that does a lot of computation in such a function). It's
not super easy to solve, but it's approachable because the Pd-GUI
already exists. But that's a completely separate issue from getting
something like GEM to run in its own thread.
Things maybe acceptable to us PD "grey beards", but at some point it would be nice to find a way to
enter the modern, multicore multithreaded world. Moores law has shifted from clock speed to "just add
more cores" years ago now, so it's not like "buy a faster machine" is going to magically solve
single threaded speed issues.
It's not acceptable, but if you want to move forward _and_ do work that
will be in sync with or accepted into Pd vanilla I don't see a way
forward. I can't even get help docs into Pd vanilla, and they were
written to the PDDP spec that this community came up with and approved.
And as you know, there's a publicly viewable list of the same exact
frustrations from all kinds of developers with various styles of
communication.
At the very least, we should be able to run a performance intensive GEM patch
with real time audio without drop outs *while* editing.
Did you use any of the Pd-l2ork versions before it moved to Tkpath? It
didn't solve the *_getrect problem I mentioned above, but it solved a
whole lot of the problems that cause dropouts while editing, mainly by
shooting way fewer messages across the socket.
Anyway if you're interested in coding anything up related to this
thread, I know Ivica is interested in solving the GEM issue you mentioned.
-Jonathan
Oh wait, that's called Max MSP. :D And that is perhaps the reasonable stance
taken by a certain teaching institution I just left who is really only
interested in PD on places where Max currently can't be used, like Raspberry PI.
enohp ym morf tnes
--------------
Dan Wilcox
danomatika.com
robotcowboy.com
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