将判题控制器由多线程修改为多进程

我一定是sb了，使用Python的多线程跑cpu密集型的应用。
由于Python的GIL的存在，导致在cpu上每次只能有一个线程在运行。如果一个线程运行，而且cpu时间是3秒的话，那实际运行时间将大约3秒。如果两个线程同时在进行，那总运行时间几乎要翻倍。

而换用多进程之后，单个进行运行实际时间只是稍微大于cpu时间，两个进程同时运行的时候，总的时间也是cpu时间稍微增加。

同时Python2在多进程之间运行类方法的时候存在bug，使用了 http://stackoverflow.com/questions/1816958/cant-pickle-type-instancemethod-when-using-pythons-multiprocessing-pool-ma/7309686#7309686 的方法进行patch。然后不同进程之间共享的时候，要防止循环依赖，参考 http://stackoverflow.com/questions/25382455/python-notimplementederror-pool-objects-cannot-be-passed-between-processes

judge/client.py

@@ -2,11 +2,32 @@
 import json
 import time
 import commands
-from Queue import Queue
+from multiprocessing import Pool
-from thread_pool import ThreadPool
 from settings import max_running_number, lrun_gid, lrun_uid, use_tmpfs
 from consts import Language, Result
 
+from copy_reg import pickle
+from types import MethodType
+
+
+# 下面两个函数告诉Python怎么pickle类实例中的方法，否则Python2会报错，是Python2的已知bug
+def _pickle_method(method):
+    func_name = method.im_func.__name__
+    obj = method.im_self
+    cls = method.im_class
+    return _unpickle_method, (func_name, obj, cls)
+
+
+def _unpickle_method(func_name, obj, cls):
+    for cls in cls.mro():
+        try:
+            func = cls.__dict__[func_name]
+        except KeyError:
+            pass
+        else:
+            break
+    return func.__get__(obj, cls)
+
 
 class JudgeClientException(Exception):
     pass
@@ -15,24 +36,25 @@ class JudgeClientException(Exception):
 class JudgeClient(object):
     def __init__(self, language, exec_file_path, max_cpu_time,
                  max_real_time, max_memory, test_case_dir):
-        # 语言 c cpp 或者 java
+        """
+        :param language: 语言，见consts.py
+        :param exec_file_path: 可执行文件路径
+        :param max_cpu_time: 最大cpu时间，单位ms
+        :param max_real_time: 最大执行时间，单位ms
+        :param max_memory: 最大内存，单位MB
+        :param test_case_dir: 测试用户文件夹路径
+        :return:返回结果list
+        """
         self.language = language
-        # 可执行文件路径，比如 /root/1/a.out /root/1/Main.class
         self.exec_file_path = exec_file_path
-        # 最大的cpu时间 单位ms
         self.max_cpu_time = max_cpu_time
-        # 最大实际运行时间 单位ms
         self.max_real_time = max_real_time
-        # 最大cpu占用，注意不要小于500000 单位byte
         self.max_memory = max_memory
-        # 测试用例文件路径，比如/root/testcase/1/
         self.test_case_dir = test_case_dir
-        # 判题结果队列
+        # 进程池
-        self.result_queue = Queue()
+        self.pool = Pool(processes=max_running_number)
-        # 线程池
+        # 结果数组
-        self.thread_pool = ThreadPool(size=max_running_number,
+        self.results = []
-                                      result_queue=self.result_queue)
-        self.thread_pool.start()
         # 测试用例配置项
         self.test_case_info = self.load_test_case_info()
 
@@ -67,9 +89,9 @@ class JudgeClient(object):
         # todo 系统调用白名单 chroot等参数
         # fixme 时间的单位问题
         command = "lrun" + \
-                  " --max-cpu-time " + str(self.max_cpu_time) + \
+                  " --max-cpu-time " + str(self.max_cpu_time / 1000.0) + \
-                  " --max-real-time " + str(self.max_real_time) + \
+                  " --max-real-time " + str(self.max_real_time / 1000.0) + \
-                  " --max-memory " + str(self.max_memory) + \
+                  " --max-memory " + str(self.max_memory * 1000 * 1000) + \
                   " --network false" + \
                   " --uid " + str(lrun_uid) + \
                   " --gid " + str(lrun_gid)
@@ -98,6 +120,8 @@ class JudgeClient(object):
                      "CPU_TIME": "cpu_time",
                      "REALTIME": "real_time",
                      "REAL_TIME": "real_time",
+                     "TERMSIG": "term_sig",
+                     "SIGNALED": "siginaled",
                      "EXITCODE": "exit_code",
                      "EXCEED": "exceed"}
         for line in lines:
@@ -112,6 +136,10 @@ class JudgeClient(object):
                 result[translate[name]] = float(value) * 1000
             elif name == "EXITCODE":
                 result[translate[name]] = int(value)
+            elif name == "TERMSIG":
+                result[translate[name]] = int(value)
+            elif name == "SIGNALED":
+                result[translate[name]] = int(value)
             elif name == "EXCEED":
                 if value == "none":
                     result[translate[name]] = None
@@ -130,7 +158,7 @@ class JudgeClient(object):
         run_result["test_case_id"] = test_case_id
 
         # 如果返回值非0，代表非正常结束
-        if run_result["exit_code"]:
+        if run_result["exit_code"] or run_result["term_sig"] or run_result["siginaled"]:
             run_result["result"] = Result.RUNTIME_ERROR
             return run_result
 
@@ -148,22 +176,30 @@ class JudgeClient(object):
         run_result["result"] = Result.ACCEPTED
         return run_result
 
+    def collect_result(self, result):
+        self.results.append(result)
+
     def run(self):
         # 添加到任务队列
         for i in range(self.test_case_info["test_case_number"]):
-            self.thread_pool.append_job(self.judge_one, i + 1)
+            self.pool.apply_async(self.judge_one, args=(i + 1, ),
+                                  callback=self.collect_result)
+        self.pool.close()
+        self.pool.join()
+        print self.results
 
-        self.thread_pool.join()
+    def __getstate__(self):
-        self.thread_pool.stop()
+        # 不同的pool之间进行pickle的时候要排除自己，否则报错
-
+        self_dict = self.__dict__.copy()
-        for i in range(self.test_case_info["test_case_number"]):
+        del self_dict['pool']
-            print self.result_queue.get(block=False)
+        return self_dict
 
 
+pickle(MethodType, _pickle_method, _unpickle_method)
 client = JudgeClient(language=Language.C,
                      exec_file_path="/var/judge/a.out",
-                     max_cpu_time=1000,
+                     max_cpu_time=1000000,
-                     max_real_time=2000,
+                     max_real_time=200000,
-                     max_memory=600000,
+                     max_memory=1,
                      test_case_dir="/var/test_case/1/")
 client.run()