Phil Stone wrote:
This has been a fascinating thread about the direction of PD.
I've been thinking about parallelism and PD as multi-core processors become common. How hard would it be to make PD able to take advantage of parallel architecture? I'm guessing that it is decidedly non-trivial, as lack of threading is already an issue in contention between the GUI and audio processing.
Without some support for parallelism, PD could be going as fast as it will ever go -- the trend seems to be that CPU speeds will not be climbing much (at least not dramatically like they have until now), and increasing numbers of cores will be the path to greater speed and power.
Is there any hope in this direction?
Phil Stone
I had a discussion with matju in #dataflow [1] last week about possible directions for multithreading in Pd. The general conclusions we reached were roughly:
threading/parallelism is necessary, and will become more necessary
trying to automatically split the computational load between multiple
threads will be very difficult and the result sub-optimal
solution: a primitive in Pd for manually controlled threading
the existing threading externals are error prone, because you need
object delimiters at all boundaries of the non-specific region to be threaded, otherwise horrible crashes can result
- methods already exist in Pd for defining specific regions, namely
abstractions and subpatches
- there are already objects that change the properties of those
specific regions, namely [block~] and [switch~]
- a similar object could be created to make a specific region a
separate thread, which would change the behaviour of [inlet] [outlet] etc to communicate between threads, much like [block~] changes the behaviour of [inlet~] etc to communicate between different signal vector block sizes.
- arguments and messages to the [thread] object (or however it is
named) could adjust the thread priority, or other parameters.
Claude
[1] irc://irc.freenode.net/#dataflow