Merge pull request #10620 from reyoung/feature/trainer_by_pe

Draft for train by parallel executor

python/paddle/fluid/tests/book/high-level-api/recognize_digits/test_recognize_digits_conv.py

@@ -62,7 +62,10 @@ def train(use_cuda, train_program, save_dirname):
     optimizer = fluid.optimizer.Adam(learning_rate=0.001)
 
     trainer = fluid.Trainer(
-        train_func=train_program, place=place, optimizer=optimizer)
+        train_func=train_program,
+        place=place,
+        optimizer=optimizer,
+        parallel=True)
 
     def event_handler(event):
         if isinstance(event, fluid.EndEpochEvent):
@@ -87,6 +90,9 @@ def train(use_cuda, train_program, save_dirname):
                     event.epoch + 1, float(avg_cost), float(acc)))
                 if math.isnan(float(avg_cost)):
                     sys.exit("got NaN loss, training failed.")
+        elif isinstance(event, fluid.EndStepEvent):
+            print("Step {0}, Epoch {1} Metrics {2}".format(
+                event.step, event.epoch, map(numpy.array, event.metrics)))
 
     train_reader = paddle.batch(
         paddle.reader.shuffle(
@@ -131,4 +137,4 @@ def main(use_cuda):
 
 if __name__ == '__main__':
     # for use_cuda in (False, True):
-    main(use_cuda=False)
+    main(use_cuda=True)

python/paddle/fluid/trainer.py

@@ -20,6 +20,7 @@ import data_feeder
 import contextlib
 import io
 import unique_name
+import parallel_executor
 
 # optimizer is same as the parameter of Trainer.__init__. Rename it to opt_module
 import optimizer as opt_module
@@ -48,12 +49,14 @@ class BeginStepEvent(object):
     def __init__(self, epoch_id, step_id):
         self.epoch = epoch_id
         self.step = step_id
+        self.fetch_metrics = True
 
 
 class EndStepEvent(object):
-    def __init__(self, epoch_id, step_id):
+    def __init__(self, epoch_id, step_id, metrics):
         self.epoch = epoch_id
         self.step = step_id
+        self.metrics = metrics
 
 
 def check_and_get_place(place):
@@ -87,12 +90,17 @@ class Trainer(object):
 
     Args:
         train_func(callable): A function which will return loss. The loss must be a scalar.
-        infer_func(callable): A function which will return predict, used to save inference model
         optimizer(optimizer.Optimizer): The optimizer should be an instance of Optimizer
         place: The device place of this trainer.
     """
 
-    def __init__(self, train_func, optimizer, param_path=None, place=None):
+    def __init__(self,
+                 train_func,
+                 optimizer,
+                 param_path=None,
+                 place=None,
+                 parallel=False):
+        self.parallel = parallel
         # 1. we need to generate a framework.Program by calling
         # program_func. Reference: fluid.program_guard in
         # test_word2vec.py
@@ -106,14 +114,14 @@ class Trainer(object):
 
         with framework.program_guard(self.train_program, self.startup_program):
             program_func_outs = train_func()
-            self.test_outputs = program_func_outs if isinstance(
+            self.train_func_outputs = program_func_outs if isinstance(
                 program_func_outs, list) else [program_func_outs]
             self.test_program = self.train_program.clone()
             if not isinstance(optimizer, opt_module.Optimizer):
                 raise TypeError(
                     "The optimizer should be an instance of Optimizer")
             # The fisrt element of program_func_outs is loss.
-            loss = self.test_outputs[0]
+            loss = self.train_func_outputs[0]
             optimize_ops, params_grads = optimizer.minimize(loss)
 
         self.place = check_and_get_place(place)
@@ -202,12 +210,7 @@ class Trainer(object):
                     'TRAINING_ROLE environment variable must be either TRAINER or PSERVER'
                 )
 
-    def train(self,
-              num_epochs,
-              event_handler,
-              reader,
-              feed_order,
-              parallel=False):
+    def train(self, num_epochs, event_handler, reader=None, feed_order=None):
         """
         Train the model.
 
@@ -215,25 +218,24 @@ class Trainer(object):
             num_epochs: The number of epoch. An epoch will process all data in reader
             event_handler: The event handler. A function with type (ev:Event)->void
             reader:
-            parallel: True if use multi-CPUs or multi-GPUs
             feed_order: Feeding order of reader. None will following the defining
                 order in program
 
         Returns:
 
         """
-        if parallel:
-            raise NotImplementedError(
-                "Parallel Executor version of trainer is not implemented")
-
         training_role = os.getenv("PADDLE_TRAINING_ROLE", "")
         if training_role == "PSERVER":
             with self._prog_and_scope_guard():
                 exe = executor.Executor(self.place)
                 exe.run()
                 return
-
-        self._train_by_executor(num_epochs, event_handler, reader, feed_order)
+        if self.parallel:
+            self._train_by_parallel_executor(num_epochs, event_handler, reader,
+                                             feed_order)
+        else:
+            self._train_by_executor(num_epochs, event_handler, reader,
+                                    feed_order)
 
     def test(self, reader, feed_order):
         """
@@ -245,7 +247,8 @@ class Trainer(object):
                 order in program
         """
 
-        return self._test_by_executor(reader, feed_order, self.test_outputs)
+        return self._test_by_executor(reader, feed_order,
+                                      self.train_func_outputs)
 
     def save_params(self, param_path):
         # reference: save_persistables in io.py
@@ -279,12 +282,24 @@ class Trainer(object):
             feeder = data_feeder.DataFeeder(
                 feed_list=feed_var_list, place=self.place)
             exe = executor.Executor(self.place)
+            reader = feeder.decorate_reader(reader, multi_devices=False)
+            self._train_by_any_executor(event_handler, exe, num_epochs, reader)
+
+    def _train_by_any_executor(self, event_handler, exe, num_epochs, reader):
         for epoch_id in range(num_epochs):
             event_handler(BeginEpochEvent(epoch_id))
             for step_id, data in enumerate(reader()):
-                    event_handler(BeginStepEvent(epoch_id, step_id))
-                    exe.run(feed=feeder.feed(data), fetch_list=[])
-                    event_handler(EndStepEvent(epoch_id, step_id))
+                begin_event = BeginStepEvent(epoch_id, step_id)
+                event_handler(begin_event)
+                if begin_event.fetch_metrics:
+                    metrics = exe.run(feed=data,
+                                      fetch_list=[
+                                          var.name
+                                          for var in self.train_func_outputs
+                                      ])
+                else:
+                    metrics = exe.run(feed=data, fetch_list=[])
+                event_handler(EndStepEvent(epoch_id, step_id, metrics))
             event_handler(EndEpochEvent(epoch_id))
 
     def _test_by_executor(self, reader, feed_order, fetch_list):
@@ -304,6 +319,28 @@ class Trainer(object):
 
             return [x / count for x in accumulated]
 
+    def _train_by_parallel_executor(self, num_epochs, event_handler, reader,
+                                    feed_order):
+        with self._prog_and_scope_guard():
+            pe = self._get_or_create_parallel_executor()
+            feed_var_list = build_feed_var_list(self.train_program, feed_order)
+            feeder = data_feeder.DataFeeder(
+                feed_list=feed_var_list, place=self.place)
+            reader = feeder.decorate_reader(reader, multi_devices=True)
+            for epoch_id in range(num_epochs):
+                self._train_by_any_executor(event_handler, pe, num_epochs,
+                                            reader)
+
+    def _get_parallel_executor(self):
+        return getattr(self, 'parallel_executor', None)
+
+    def _get_or_create_parallel_executor(self):
+        if self._get_parallel_executor() is None:
+            self.parallel_executor = parallel_executor.ParallelExecutor(
+                use_cuda=isinstance(self.place, core.CUDAPlace),
+                loss_name=self.train_func_outputs[0].name)
+        return self._get_parallel_executor()
+
 
 def build_feed_var_list(program, feed_order):
     if not isinstance(program, framework.Program):