Question

我在year_queue中有一个大约15年的列表，我需要每年生成一个进程。但是根据我运行代码的服务器，处理器的数量会有所不同。如何根据服务器中的处理器数量动态改变变量num_processes？

如果我设置了num_processes＆gt;处理器的数量，会自动产生相应的产生吗？当我测试它时 - 它创建了15个进程＆amp;在它们之间分配CPU电源。我正在寻找一种方法来首先创建'n'个进程，其中n =服务器中的处理器数量，然后当每个进程完成时，下一个进程生成。

for i in range(num_processes):
    worker = ForEachPerson(year_queue, result_queue, i, dict_of_files)
    print "worker spawned for " + str(i)
    worker.start()

results = []
while len(results) < len(years):
    result = result_queue.get()
    results.append(result)

任何人都有同样的问题吗？

while year_queue.empty() != True:
    for i in range(num_processes):
      worker = ForEachPerson(year_queue, result_queue, i, dict_of_files)
      print "worker spawned for " + str(i)
      worker.start()

    # collect results off the queue
    print "results being collected"
    results = []
    while len(results) < len(num_processes):
      result = result_queue.get()
      results.append(result)

Answer 1

使用multiprocessing Pool。该课程完成了为您选择正确数量的流程并运行它们的所有繁琐工作。它也不会为每个任务生成一个新进程，但是一旦完成就重用它们。

def process_year(year):
    ...
    return result

pool = multiprocessing.Pool()
results = pool.map(process_year, year_queue)

Answer 2

from multiprocessing import Process, Queue, cpu_count
from Queue import Empty

class ForEachPerson(Process):
    def __init__(self, year_queue, result_queue, i, dict_of_files):
        self.year_queue=year_queue
        self.result_queue=result_queue
        self.i=i
        self.dict_of_files=dict_of_files
        super(ForEachPerson, self).__init__()

    def run(self):
        while True:
            try:
                year=self.year_queue.get()

                ''' Do something '''

                self.result_queue.put(year)
            except Empty:
                self.result_queue.close()
                return

if __name__ == '__main__':
    year_queue=Queue()
    result_queue=Queue()
    dict_of_files={}

    start_year=1996
    num_years=15

    for year in range(start_year, start_year + num_years):
        year_queue.put(year)

    workers=[]
    for i in range(cpu_count()):
        worker = ForEachPerson(year_queue, result_queue, i, dict_of_files)
        print 'worker spawned for', str(i)
        worker.start()
        workers.append(worker)

    results=[]
    while len(results) < num_years:
        try:
            year=result_queue.get()
            results.append(year)
            print 'Result:', year
        except Empty:
            pass

    for worker in workers:
        worker.terminate()

动态计算要生成的进程数

2 个答案: