Python语言及其应用（第2版）

进程和并发

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249

result = math.sqrt(float(val))

return result

def use_threads(num, values):

t1 = time.time()

with futures.ThreadPoolExecutor(num) as tex:

results = tex.map(calc, values)

t2 = time.time()

return t2 - t1

def use_processes(num, values):

t1 = time.time()

with futures.ProcessPoolExecutor(num) as pex:

results = pex.map(calc, values)

t2 = time.time()

return t2 - t1

def main(workers, values):

print(f"Using {workers} workers for {len(values)} values")

t_sec = use_threads(workers, values)

print(f"Threads took {t_sec:.4f} seconds")

p_sec = use_processes(workers, values)

print(f"Processes took {p_sec:.4f} seconds")

if __name__ ...