CircuitPython - a Python implementation for teaching coding with microcontrollers https://git.suspectdevices.com/suspect-devices/circuitpython/atom?h=5.3.x 2019-11-20T20:37:13+00:00 2019-11-20T20:37:13+00:00 Jeff Epler jepler@gmail.com 2019-11-20T16:15:44+00:00 urn:sha1:46c5775ba4b9c4905f8e3f4c1842c2c6c04d8fb0 2019-11-20T20:37:13+00:00 Jeff Epler jepler@gmail.com 2019-11-20T16:15:33+00:00 urn:sha1:a9baa0f954ec757ef1e3990af136a4f0b3cb2b1e 2019-11-20T20:37:13+00:00 Jeff Epler jepler@gmail.com 2019-11-20T16:15:11+00:00 urn:sha1:70719597ab7b3785a6641b08ef3cb82d9b6b459b 2019-11-18T17:26:48+00:00 Jeff Epler jepler@gmail.com 2019-11-18T15:53:12+00:00 urn:sha1:568636d562b4c64d0095ff2ac921b79eb69e520d This improves performance of running python code by 34%, based on the "pystone" benchmark on metro m4 express at 5000 passes (1127.65 -> 1521.6 passes/second). In addition, by instrumenting the tick function and monitoring on an oscilloscope, the time actually spent in run_background_tasks() on the metro m4 decreases from average 43% to 0.5%. (however, there's some additional overhead that is moved around and not accounted for in that "0.5%" figure, each time supervisor_run_background_tasks_if_tick is called but no tick has occurred) On the CPB, it increases pystone from 633 to 769, a smaller percentage increase of 21%. I did not measure the time actually spent in run_background_tasks() on CPB. Testing performed: on metro m4 and cpb, run pystone adapted from python3.4 (change time.time to time.monotonic for sub-second resolution) Besides running a 5000 pass test, I also ran a 50-pass test while scoping how long an output pin was set. Average: 34.59ms or 1445/s on m4, 67.61ms or 739/s on cbp, both matching the other pystone result reasonably well. import pystone import board import digitalio import time d = digitalio.DigitalInOut(board.D13) d.direction = digitalio.Direction.OUTPUT while True: d.value = 0 time.sleep(.01) d.value = 1 pystone.main(50) 2019-11-18T17:01:23+00:00 Jeff Epler jepler@gmail.com 2019-11-18T14:22:41+00:00 urn:sha1:7f744a2369a5036cadfa05575da1704f709c98bb This code is shared by most parts, except where not all the #ifdefs inside the tick function were present in all ports. This mostly would have broken gamepad tick support on non-samd ports. The "ms32" and "ms64" variants of the tick functions are introduced because there is no 64-bit atomic read. Disabling interrupts avoids a low probability bug where milliseconds could be off by ~49.5 days once every ~49.5 days (2^32 ms). Avoiding disabling interrupts when only the low 32 bits are needed is a minor optimization. Testing performed: on metro m4 express, USB still works and time.monotonic_ns() still counts up