Merge branch 'better-a3c'

tensorpack/train/trainer.py

@@ -17,7 +17,8 @@ from ..utils.concurrency import LoopThread
 from ..tfutils.summary import summary_moving_average
 from ..tfutils import *
 
-__all__ = ['SimpleTrainer', 'QueueInputTrainer', 'start_train']
+__all__ = ['SimpleTrainer', 'QueueInputTrainer',
+        'AsyncMultiGPUTrainer', 'SyncMultiGPUTrainer']
 
 class SimpleTrainer(Trainer):
     def run_step(self):
@@ -269,7 +270,9 @@ class QueueInputTrainer(Trainer):
         return [self.get_predict_func(input_names, output_names, k)
                 for k in range(n)]
 
-def start_train(config):
-    tr = QueueInputTrainer(config)
-    tr.train()
+def AsyncMultiGPUTrainer(config):
+    return QueueInputTrainer(config, async=True)
+
+def SyncMultiGPUTrainer(config):
+    return QueueInputTrainer(config)
 

tensorpack/utils/concurrency.py

@@ -55,28 +55,33 @@ class StoppableThread(threading.Thread):
             except queue.Empty:
                 pass
 
-class LoopThread(threading.Thread):
+class LoopThread(StoppableThread):
     """ A pausable thread that simply runs a loop"""
-    def __init__(self, func):
+    def __init__(self, func, pausable=True):
         """
         :param func: the function to run
         """
         super(LoopThread, self).__init__()
-        self.func = func
-        self.lock = threading.Lock()
+        self._func = func
+        self._pausable = pausable
+        if pausable:
+            self._lock = threading.Lock()
         self.daemon = True
 
     def run(self):
-        while True:
-            self.lock.acquire()
-            self.lock.release()
-            self.func()
+        while not self.stopped():
+            if self._pausable:
+                self._lock.acquire()
+                self._lock.release()
+            self._func()
 
     def pause(self):
-        self.lock.acquire()
+        assert self._pausable
+        self._lock.acquire()
 
     def resume(self):
-        self.lock.release()
+        assert self._pausable
+        self._lock.release()
 
 
 class DIE(object):