Python线程和锁
我有一些代码如下所示：Python线程和锁,python,multithreading,locking,pyspin,Python,Multithreading,Locking,Pyspin,我有一些代码如下所示： #!/usr/bin/env python """ test out threading with PySpin and matplotlib """ import datetime import threading from matplotlib import pyplot as plt import PySpin __LOCK = threading.Lock() # Set up figure __FIG = plt.figure() __AXES = _
#!/usr/bin/env python
""" test out threading with PySpin and matplotlib """
import datetime
import threading
from matplotlib import pyplot as plt
import PySpin
__LOCK = threading.Lock()
# Set up figure
__FIG = plt.figure()
__AXES = __FIG.add_axes([0, 0, 1, 1])
# Get camera
__SYSTEM = PySpin.System.GetInstance()
__CAM = __SYSTEM.GetCameras().GetByIndex(0)
def test():
""" test thread for streaming image """
while True:
with __LOCK:
print('test thread: ' + str(datetime.datetime.now()))
image = get_image() # pylint: disable=unused-variable
def get_image():
""" grabs image and returns numpy array """
image = __CAM.GetNextImage()
# Initialize image data
image_data = None
# Ensure image is complete
if not image.IsIncomplete():
# Get image data
image_data = image.GetNDArray()
# Release image
image.Release()
return image_data
def main():
""" test """
# Start Acquisition
__CAM.Init()
__CAM.BeginAcquisition()
# Start thread
thread = threading.Thread(target=test)
thread.start()
# Update plot
while True:
#import time
#time.sleep(0.01)
with __LOCK:
print('primary thread: ' + str(datetime.datetime.now()))
plt.pause(0.01)
return 0
if __name__ == '__main__':
main()
primary thread: 2018-04-30 21:21:49.297240
primary thread: 2018-04-30 21:21:49.325118
primary thread: 2018-04-30 21:21:49.352918
primary thread: 2018-04-30 21:21:49.381198
primary thread: 2018-04-30 21:21:49.408484
primary thread: 2018-04-30 21:21:49.436476
primary thread: 2018-04-30 21:21:49.463705
primary thread: 2018-04-30 21:21:49.492506
primary thread: 2018-04-30 21:21:49.520737
primary thread: 2018-04-30 21:21:49.548624
primary thread: 2018-04-30 21:21:49.577559
primary thread: 2018-04-30 21:21:49.604856
primary thread: 2018-04-30 21:21:49.633234
test thread: 2018-04-30 21:21:49.660484
test thread: 2018-04-30 21:21:49.661107
test thread: 2018-04-30 21:21:49.661617
test thread: 2018-04-30 21:21:49.662168
test thread: 2018-04-30 21:21:49.662787
test thread: 2018-04-30 21:21:49.663385
test thread: 2018-04-30 21:21:49.664000
test thread: 2018-04-30 21:21:49.664629
test thread: 2018-04-30 21:21:49.665230
test thread: 2018-04-30 21:21:49.665864
test thread: 2018-04-30 21:21:49.666540
test thread: 2018-04-30 21:21:49.669028
test thread: 2018-04-30 21:21:49.676831
primary thread: 2018-04-30 21:21:49.683702
primary thread: 2018-04-30 21:21:49.711935
primary thread: 2018-04-30 21:21:49.739462
primary thread: 2018-04-30 21:21:49.767674
primary thread: 2018-04-30 21:21:49.795136
primary thread: 2018-04-30 21:21:49.822378
primary thread: 2018-04-30 21:21:49.849625
primary thread: 2018-04-30 21:21:49.877958
primary thread: 2018-04-30 21:21:49.905631
primary thread: 2018-04-30 21:21:49.932940
primary thread: 2018-04-30 21:21:49.960137
primary thread: 2018-04-30 21:21:49.987946
primary thread: 2018-04-30 21:21:50.015238
primary thread: 2018-04-30 21:21:50.042956
primary thread: 2018-04-30 21:21:50.070503
我不明白的是，为什么它在切换到另一个线程之前在一个线程上“卡”了很长时间？我想，当一个线程拥有锁时，另一个线程会等待，并在另一个线程释放锁时获取锁，但这里的情况似乎不是这样…：-（@cᴏʟᴅsᴘᴇᴇᴅ 因此，我不想在这里听起来太消极，但是如果发生这种情况，在python中使用带锁的线程库有什么意义呢？它看起来几乎毫无用处。事实上，他们正在努力在即将发布的python版本中消除它。因为线程对于IO绑定的并发仍然很有用。这与“无用”有很大不同-你需要知道适合这项工作的工具。这看起来很愚蠢，但我认为我已经找到了一个“解决方案”，在释放互斥锁后短暂暂停。这可能会让其他线程有机会获得锁。