Python进阶:GIL（全局解释器锁）

def CountDown(n):
    while n > 0:
        n -= 1

# CountDown(100000000)
#==8秒

from threading import Thread

n = 100000000

t1 = Thread(target=CountDown, args=[n // 2])
t2 = Thread(target=CountDown, args=[n // 2])
t1.start()
t2.start()
t1.join()
t2.join()
#==9s

for (;;) {
    if (--ticker < 0) {
        ticker = check_interval;
    
        /* Give another thread a chance */
        PyThread_release_lock(interpreter_lock);
    
        /* Other threads may run now */
    
        PyThread_acquire_lock(interpreter_lock, 1);
    }

    bytecode = *next_instr++;
    switch (bytecode) {
        /* execute the next instruction ... */ 
    }
}

n = 0
lock = threading.Lock()

def foo():
    global n
    with lock:
        n += 1