Python中time.sleep异常，需实现128次/秒函数执行且不影响OpenGL渲染

需求 #

需要实现一个每秒执行128次的函数，同时后台运行PyOpenGLTk的OpenGL上下文，保证渲染帧率不受影响。

初始实现代码 #

import time, threading

run_counter = 0

def runner():
    global run_counter

    while True:
        do_something()
        run_counter += 1
        time.sleep(1/128)

threading.Thread(target=runner).start()

执行次数统计代码 #

while True:
    print(run_counter)
    run_counter = 0
    time.sleep(1)

遇到的问题 #

• 理论上time.sleep(1/128)能让函数每秒执行128次，但实际统计只有64次。
• 后台运行基于PyOpenGLTk的OpenGL上下文，相关代码如下：

OpenGL画布类 #

class WindowGLTkCanvas(OpenGLFrame):

    def __init__(self, parent, root, size: Dimension = Dimension(100, 100), scale=1):

        OpenGLFrame.__init__(self, root, width=size.x, height=size.y)
        PynamicsObject.__init__(self, parent)
        self.parent = parent
        self.renderable = []
        self.scale = scale

        self.texture_handler = {}

        self.width = size.x
        self.height = size.y

        self.frame = Routine(self, target=self.redraw)


    def initgl(self):
        Logger.info("Call: initgl")
        glViewport(0, 0, self.width, self.height)
        glClearColor(0, 0, 0, 0)

        # 设置投影矩阵
        glMatrixMode(GL_PROJECTION)
        glLoadIdentity()
        glOrtho(0, self.width, self.height, 0, -1, 1)

        # 设置模型视图矩阵
        glMatrixMode(GL_MODELVIEW)
        glLoadIdentity()

        glEnable(GL_TEXTURE_2D)
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
        glEnable(GL_BLEND)
        #glEnable(GL_LINE_SMOOTH)

    def redraw(self):

        Logger.info("Call: draw")

        glClear(GL_COLOR_BUFFER_BIT)
        glFlush()

        #Logger.info("Call: drawend")

Tkinter包装类 #

class WindowGLTk():

    def __init__(self, parent):
        super().__init__(parent)

        self.root = tk.Tk()
        self.gl_canvas = WindowGLTkCanvas(self, self.root, Dim(500, 500))
        self.gl_canvas.pack(fill=tk.BOTH, expand=tk.YES)
        self.gl_canvas.animate = True

        self.parent._viewport = self

        #self.frame = Routine(self, self._tick, delay=tps_to_seconds(200))

    def _tick(self):
        print("RENDER")
        #self.gl_canvas.redraw()

    def load(self):
        self.root.mainloop()

尝试的替代方案及问题 #

实现轮询式睡眠函数：

def sleep(seconds: float):
    a = time.time()
    b = a + seconds
    while time.time() < b:
        pass

    return

该方案能让目标函数稳定每秒执行128次，但会导致PyOpenGLTk的redraw函数帧率远低于预期的144FPS。

自行解决的方案 #

采用定时批量启动任务的方式，虽显繁琐但有效：

def _loop(self):
    while True:
        for i in range(128):
            threading.Timer(i / 128, self.target).start()
        time.sleep(1)

内容的提问来源于stack exchange，提问作者relizc