!451 use forkserver multiprocess context to avoid forking child process with locked stream resource(eg stdout)

Merge pull request !451 from wenkai/wk5_fix_log_stream_flush_stuck

mindinsight/utils/computing_resource_mgr.py

@@ -16,6 +16,7 @@
 import fractions
 import math
 import threading
+import multiprocessing
 from concurrent import futures
 
 from mindinsight.utils.log import utils_logger as logger
@@ -23,6 +24,9 @@ from mindinsight.utils.constant import GeneralErrors
 from mindinsight.utils.exceptions import MindInsightException
 
 
+_MP_CONTEXT = multiprocessing.get_context(method="forkserver")
+
+
 class ComputingResourceManager:
     """
     Manager for computing resources.
@@ -44,7 +48,7 @@ class ComputingResourceManager:
             for ind in range(self._executors_cnt)
         }
         self._remaining_executors = len(self._executors)
-        self._backend = futures.ProcessPoolExecutor(max_workers=max_processes_cnt)
+        self._backend = futures.ProcessPoolExecutor(max_workers=max_processes_cnt, mp_context=_MP_CONTEXT)
         logger.info("Initialized ComputingResourceManager with executors_cnt=%s, max_processes_cnt=%s.",
                     executors_cnt, max_processes_cnt)