I needed to remind myself the “suggestions” concerning threading vs multi-processing,
(ignoring the messaging/synchronization differences),
so I created some quick comparison tests.
Examples run on Raspberry Pi 3B 1.2GHz 4-core with Python3.7.3
– ( With other processes running including htop )
Summary
(For this test) Multiprocessing and threading had similar results for i/o bound,
but multi-processing was more efficient than threading for cpu-bound.
Using threads:
Typical Result:
. Starting 4000 cycles of io-bound threading
. Sequential run time: 39.15 seconds
. 4 threads Parallel run time: 18.19 seconds
. 2 threads Parallel - twice run time: 20.61 seconds
Typical Result:
. Starting 4000000 cycles of cpu-only threading
. Sequential run time: 9.39 seconds
. 4 threads Parallel run time: 10.19 seconds
. 2 threads Parallel twice - run time: 9.58 seconds
Using multiprocessing:
Typical Result:
. Starting 4000 cycles of io-bound processing
. Sequential - run time: 39.74 seconds
. 4 procs Parallel - run time: 17.68 seconds
. 2 procs Parallel twice - run time: 20.68 seconds
Typical Result:
. Starting 4000000 cycles of cpu-only processing
. Sequential run time: 9.24 seconds
. 4 procs Parallel - run time: 2.59 seconds
. 2 procs Parallel twice - run time: 4.76 seconds