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multitask-thoughts

2014-07-19

thoughts on multitasking

Presentation on coroutines as a python OS mechanism
- http://www.dabeaz.com/coroutines/Coroutines.pdf
- no word of real time/timing
- suggested next steps (search on http://pypi.python.org)
  - https://pypi.python.org/pypi/cogen/0.2.1
  - multitask
  - https://pypi.python.org/pypi/greenlet/0.4.2
  - eventlet
  - kamaelia

another survey
- https://wiki.python.org/moin/Concurrency/
- https://wiki.python.org/moin/ParallelProcessing

cogen
- has strange api, unpacks arrays for some reason.

multiprocessing/multithreading

http://stackoverflow.com/questions/3044580/multiprocessing-vs-threading-python
serious work needs to be put into state sharing and safety

scrim

just make something that works

the dream

def ticker():
    while True:
        tick()
        sleep(.01)
def controller():
    while True:
        control()
        sleep(.001)

sched.add(ticker)
sched.add(controller)
sched.startAll()

easiest implementation
- different notebooks, different process.
- hard part: state sharing
  - http://mpi4py.scipy.org/docs/usrman/tutorial.html#point-to-point-communication

todo
- measure latency/control frequency over lcm multiprocess