Remove DataParallel.scale_loss & apply_collective_grads (#27603)

* remove data parallel scale loss & apply collective_grads

* move apply in minimize

* fix failed unittests

python/paddle/fluid/dygraph/varbase_patch_methods.py

@@ -13,12 +13,15 @@
 # limitations under the License.
 
 import inspect
+import numpy as np
+
+import paddle
 from .. import framework
 from .. import core
 from ..framework import Variable, Parameter, ParamBase
 from .base import switch_to_static_graph
-import numpy as np
 from .math_op_patch import monkey_patch_math_varbase
+from .parallel import scale_loss
 
 
 def monkey_patch_varbase():
@@ -165,7 +168,12 @@ def monkey_patch_varbase():
 
         """
         if framework.in_dygraph_mode():
-            self._run_backward(framework._dygraph_tracer(), retain_graph)
+            if paddle.distributed.get_world_size() > 1:
+                scaled_loss = scale_loss(self)
+                scaled_loss._run_backward(framework._dygraph_tracer(),
+                                          retain_graph)
+            else:
+                self._run_backward(framework._dygraph_tracer(), retain_graph)
         else:
             raise ValueError(
                 "Variable.backward() is only available in DyGraph mode")

python/paddle/fluid/optimizer.py

@@ -19,8 +19,10 @@ import six
 import logging
 from collections import defaultdict
 
+import paddle
 from paddle.fluid.distribute_lookup_table import find_distributed_lookup_table
 from paddle.fluid.framework import Program, Variable, name_scope, default_main_program, default_startup_program, device_guard
+from paddle.fluid.dygraph.parallel import apply_collective_grads
 
 from . import framework
 from . import layers
@@ -40,7 +42,6 @@ from paddle.fluid.layers import tensor
 from functools import reduce
 from .wrapped_decorator import signature_safe_contextmanager
 from .. import compat as cpt
-import paddle
 
 __all__ = [
     'SGD', 'Momentum', 'Adagrad', 'Adam', 'Adamax', 'Dpsgd', 'DecayedAdagrad',
@@ -771,8 +772,14 @@ class Optimizer(object):
 
         self._dtype = loss.dtype
         if framework.in_dygraph_mode():
+            parameter_list = parameter_list if parameter_list \
+                else self._parameter_list
+
+            if paddle.distributed.get_world_size() > 1:
+                apply_collective_grads(parameter_list)
+
             params_grads = []
-            for param in self._parameter_list:
+            for param in parameter_list:
                 if not param.trainable:
                     continue
                 if param._grad_ivar() is not None:
@@ -939,6 +946,7 @@ class Optimizer(object):
 
         parameter_list = parameter_list if parameter_list \
             else self._parameter_list
+
         params_grads = self.backward(
             loss,
             startup_program=startup_program,

python/paddle/fluid/tests/unittests/test_dist_base.py

@@ -435,13 +435,7 @@ class TestParallelDyGraphRunnerBase(object):
                         "loss at step %d: %f" % (step_id, loss.numpy()))
                 out_losses.append(loss.numpy())
 
-                # FIXME(Yancey1989): scale the loss inplace
-                if args.update_method == "nccl2":
-                    loss = model.scale_loss(loss)
-
                 loss.backward()
-                if args.update_method == "nccl2":
-                    model.apply_collective_grads()
 
                 opt.minimize(loss)
                 model.clear_gradients()
@@ -477,12 +471,7 @@ class TestParallelDyGraphRunnerBase(object):
             loss = self.run_one_loop(model, opt, data)
             out_losses.append(loss.numpy())
 
-            if args.update_method == "nccl2":
-                loss = model.scale_loss(loss)
-
             loss.backward()
-            if args.update_method == "nccl2":
-                model.apply_collective_grads()
 
             opt.minimize(loss)
             model.clear_gradients()
@@ -521,12 +510,7 @@ class TestParallelDyGraphRunnerBase(object):
             loss = self.run_one_loop(model, opt, data)
             out_losses.append(loss.numpy())
 
-            if args.update_method == "nccl2":
-                loss = model.scale_loss(loss)
-
             loss.backward()
-            if args.update_method == "nccl2":
-                model.apply_collective_grads()
 
             opt.step()
             opt.clear_grad()

python/paddle/fluid/tests/unittests/test_imperative_parallel_coalesce_split.py

@@ -22,6 +22,7 @@ import paddle.fluid as fluid
 from paddle.fluid import core
 from paddle.fluid.dygraph.parallel import DataParallel
 from paddle.fluid.dygraph.base import to_variable
+from paddle.fluid.dygraph.parallel import _coalesce_tensors, _split_tensors, _reshape_inplace
 
 
 class MyLayer(fluid.Layer):
@@ -57,8 +58,8 @@ class TestImperativeParallelCoalesceSplit(unittest.TestCase):
                 orig_var_shapes.append(var.shape)
 
             # execute interface
-            coalesced_vars = test_layer._coalesce_tensors(var_groups)
-            test_layer._split_tensors(coalesced_vars)
+            coalesced_vars = _coalesce_tensors(var_groups)
+            _split_tensors(coalesced_vars)
 
             # compare
             for orig_var_shape, var in zip(orig_var_shapes, vars):
@@ -74,7 +75,7 @@ class TestImperativeParallelCoalesceSplit(unittest.TestCase):
             new_shape = [5, 10]
             x_data = np.random.random(ori_shape).astype("float32")
             x = to_variable(x_data)
-            test_layer._reshape_inplace(x, new_shape)
+            _reshape_inplace(x, new_shape)
             self.assertEqual(x.shape, new_shape)
 
 

python/paddle/optimizer/adam.py

@@ -17,6 +17,9 @@ from ..fluid import core
 from ..fluid import framework
 from ..fluid.framework import Variable
 
+import paddle
+from paddle.fluid.dygraph.parallel import apply_collective_grads
+
 __all__ = ["Adam"]
 
 
@@ -276,7 +279,9 @@ class Adam(Optimizer):
                 adam.step()
                 adam.clear_grad()
         """
-        parameter_list = self._parameter_list
+        if paddle.distributed.get_world_size() > 1:
+            apply_collective_grads(self._parameter_list)
+
         self._dtype = None
         params_grads = []
         for param in self._parameter_list:

python/paddle/optimizer/adamw.py

@@ -16,6 +16,8 @@ from .optimizer import Optimizer
 from .adam import Adam
 from ..fluid import framework
 import paddle
+from paddle.fluid.dygraph.parallel import apply_collective_grads
+
 __all__ = ['AdamW']
 
 
@@ -184,6 +186,9 @@ class AdamW(Adam):
                  startup_program=None,
                  parameters=None,
                  no_grad_set=None):
+        parameters = parameters if parameters \
+            else self._parameter_list
+
         params_grads = self.backward(
             loss=loss,
             startup_program=startup_program,
@@ -206,7 +211,9 @@ class AdamW(Adam):
 
     @framework.dygraph_only
     def step(self):
-        parameter_list = self._parameter_list
+        if paddle.distributed.get_world_size() > 1:
+            apply_collective_grads(self._parameter_list)
+
         self._dtype = None
         params_grads = []
         for param in self._parameter_list:
@@ -224,7 +231,7 @@ class AdamW(Adam):
                 updated_param = paddle.fluid.layers.elementwise_sub(
                     x=param, y=scaled_param)
                 param.set_value(updated_param.numpy())
-        optimize_ops = self._apply_optimize(
+        self._apply_optimize(
             loss=None, startup_program=None, params_grads=params_grads)
 
     def __str__(self):

python/paddle/optimizer/optimizer.py

@@ -19,9 +19,10 @@ import six
 import logging
 from collections import defaultdict
 
+import paddle
 from paddle.fluid.distribute_lookup_table import find_distributed_lookup_table
 from paddle.fluid.framework import Program, Variable, name_scope, default_main_program, default_startup_program, device_guard
-import paddle
+from paddle.fluid.dygraph.parallel import apply_collective_grads
 
 from ..fluid import framework
 from ..fluid import layers
@@ -675,8 +676,14 @@ class Optimizer(object):
 
         self._dtype = loss.dtype
         if framework.in_dygraph_mode():
+            parameter_list = parameters if parameters \
+                else self._parameter_list
+
+            if paddle.distributed.get_world_size() > 1:
+                apply_collective_grads(parameter_list)
+
             params_grads = []
-            for param in self._parameter_list:
+            for param in parameter_list:
                 if not param.trainable:
                     continue
                 if param._grad_ivar() is not None:
@@ -871,6 +878,7 @@ class Optimizer(object):
 
         parameter_list = parameters if parameters \
             else self._parameter_list
+
         params_grads = self.backward(
             loss,
             startup_program=startup_program,
@@ -907,7 +915,9 @@ class Optimizer(object):
                 adam.step()
                 adam.clear_grad()
         """
-        parameter_list = self._parameter_list
+        if paddle.distributed.get_world_size() > 1:
+            apply_collective_grads(self._parameter_list)
+
         self._dtype = None
         params_grads = []
         for param in self._parameter_list:
@@ -917,5 +927,5 @@ class Optimizer(object):
                 grad_var = param._grad_ivar()
                 params_grads.append((param, grad_var))
 
-        optimize_ops = self._apply_optimize(
+        self._apply_optimize(
             loss=None, startup_program=None, params_grads=params_grads)