Python3如何使用多线程升程序运行速度

优化前后新老代码如下：

from git_tools.git_tool import get_collect_projects, QQNews_Git
from threading import Thread, Lock
import datetime

base_url = "http://git.xx.com"
project_members_commits_lang_info = {}
lock = Lock()
threads = []

'''
Author:zenkilan
'''

def count_time(func):
  def took_up_time(*args, **kwargs):
    start_time = datetime.datetime.now()
    ret = func(*args, **kwargs)
    end_time = datetime.datetime.now()
    took_up_time = (end_time - start_time).total_seconds()
    print(f"{func.__name__} execution took up time:{took_up_time}")
    return ret

  return took_up_time

def get_project_member_lang_code_lines(git, member, begin_date, end_date):
  global project_members_commits_lang_info
  global lock
  member_name = member["username"]
  r = git.get_user_info(member_name)
  if not r["id"]:
    return
  user_commits_lang_info = git.get_commits_user_lang_diff_between(r["id"], begin_date, end_date)
  if len(user_commits_lang_info) == 0:
    return
  lock.acquire()
  project_members_commits_lang_info.setdefault(git.project, dict())
  project_members_commits_lang_info[git.project][member_name] = user_commits_lang_info
  lock.release()

def get_project_lang_code_lines(project, begin_date, end_date):
  global threads
  git = QQNews_Git(project[1], base_url, project[0])
  project_members = git.get_project_members()
  if len(project_members) == 0:
    return
  for member in project_members:
    thread = Thread(target=get_project_member_lang_code_lines, args=(git, member, begin_date, end_date))
    threads.append(thread)
    thread.start()

@count_time
def get_projects_lang_code_lines(begin_date, end_date):
  """
  获取项目代码行语言相关统计——新方法（提升效率）
  应用多线程替代for循环
  并发访问共享外部资源
  :return:
  """
  global project_members_commits_lang_info
  global threads
  for project in get_collect_projects():
    thread = Thread(target=get_project_lang_code_lines, args=(project, begin_date, end_date))
    threads.append(thread)
    thread.start()

@count_time
def get_projects_lang_code_lines_old(begin_date, end_date):
  """
  获取项目代码行语言相关统计——老方法（耗时严重）
  使用最基本的思路进行编程
  双层for循环嵌套并且每层都包含耗时操作
  :return:
  """
  project_members_commits_lang_info = {}
  for project in get_collect_projects():
    git = QQNews_Git(project[1], base_url, project[0])
    project_members = git.get_project_members()
    user_commits_lang_info_dict = {}
    if len(project_members) == 0:
      continue
    for member in project_members:
      member_name = member["username"]
      r = git.get_user_info(member_name, debug=False)
      if not r["id"]:
        continue
      try:
        user_commits_lang_info = git.get_commits_user_lang_diff_between(r["id"], begin_date, end_date)
        if len(user_commits_lang_info) == 0:
          continue
        user_commits_lang_info_dict[member_name] = user_commits_lang_info
        project_members_commits_lang_info[git.project] = user_commits_lang_info_dict
      except:
        pass
  return project_members_commits_lang_info

def test_results_equal(resultA, resultB):
  """
  测试方法
  :param resultA:
  :param resultB:
  :return:
  """
  print(resultA)
  print(resultB)
  assert len(str(resultA)) == len(str(resultB))

if __name__ == '__main__':
  from git_tools.config import begin_date, end_date

  get_projects_lang_code_lines(begin_date, end_date)
  for t in threads:
    t.join()
  old_result = get_projects_lang_code_lines_old(begin_date, end_date)
  test_results_equal(old_result, project_members_commits_lang_info)

老方法里外层for循环和内层for循环里均存在耗时操作：

1）git.get_project_members()

2）git.get_user_info(member_name, debug=False)

分两步来优化，先里后外或先外后里都行。用多线程替换for循环，并发共享外部资源，加锁避免写冲突。

测试结果通过，函数运行时间装饰器显示（单位秒）：

get_projects_lang_code_lines execution took up time:1.85294

get_projects_lang_code_lines_old execution took up time:108.604177

速度提升了约58倍

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