Kivy/Cython example of GIL vs nogil thread work

README.md

Building

Use cythonize --build cysleep.pyx

Running

After building, run python main.py

cysleep.pyx

# cython: language_level=3

cdef extern from 'time.h':
    ctypedef long time_t

    cdef struct timespec:
        time_t tv_sec
        long tv_nsec

    void nanosleep(const timespec*, timespec*) nogil


def sleep_gil(time: float):
    cdef time_t seconds = round(time)
    cdef timespec sleep_time = timespec(seconds, int((time - seconds) * 10**9))
    nanosleep(&sleep_time, NULL)


def sleep_nogil(time: float):
    cdef time_t seconds = round(time)
    cdef timespec sleep_time = timespec(seconds, int((time - seconds) * 10**9))

    with nogil:
        nanosleep(&sleep_time, NULL)

main.py

import threading

from kivy.app import App
from kivy.clock import Clock
from kivy.lang import Builder
from kivy.properties import BooleanProperty, NumericProperty

from cysleep import sleep_gil, sleep_nogil

KV = '''
BoxLayout:
    orientation: 'vertical'

    ToggleButton:
        text: 'Use nogil'
        on_state: app.use_nogil = self.state == 'down'

    Button:
        text: 'Sleep now'
        on_press: app.sleep()

        canvas:
            Color:
            Ellipse:
                pos:
                    (
                    self.center_x - self.texture_size[0] / 2 - 90,
                    self.center_y - 30
                    )
                size: 60, 60
                angle_end: app.time * 360 % 360
'''


class SleepTest(App):
    use_nogil = BooleanProperty(False)
    time = NumericProperty()

    def build(self):
        def update_time(dt):
            self.time += dt

        Clock.schedule_interval(update_time, 0)
        return Builder.load_string(KV)

    def sleep(self):
        if self.use_nogil:
            target = sleep_nogil
        else:
            target = sleep_gil

        threading.Thread(target=target, args=(1,)).start()


SleepTest().run()