fix the bug in the creation of pp groups to avoid hang (PaddlePaddle#…

…32890)

* update, test=develop

python/paddle/distributed/fleet/meta_optimizers/common.py

@@ -77,9 +77,12 @@ def _init_communicator(self,
                            wait_port,
                            global_ring_id=None,
                            sync=True):
-        nranks = len(endpoints)
-        other_endpoints = endpoints[:]
-        other_endpoints.remove(current_endpoint)
+        # if current_endpoint is None, it means just for sync,
+        # no group is created.
+        if current_endpoint:
+            nranks = len(endpoints)
+            other_endpoints = endpoints[:]
+            other_endpoints.remove(current_endpoint)
 
         if rank == 0 and wait_port:
             wait_server_ready(other_endpoints)
@@ -117,6 +120,12 @@ def _add_sync_by_allreduce(block):
                 attrs={OP_ROLE_KEY: OpRole.Forward})
 
         block = program.global_block()
+        if current_endpoint is None:
+            assert endpoints is None
+            assert sync
+            _add_sync_by_allreduce(block)
+            return
+
         if core.is_compiled_with_cuda():
             comm_id_var = block.create_var(
                 name=unique_name.generate('nccl_id'),

python/paddle/distributed/fleet/meta_optimizers/pipeline_optimizer.py

@@ -138,6 +138,9 @@ def _init_process_group(self, pipeline_pair, pipeline_ring_map):
                 first_node = pair[0] + start_index
                 second_node = pair[1] + start_index
                 if self.rank != first_node and self.rank != second_node:
+                    collective_helper._init_communicator(
+                        self.startup_program, None, None, None, None, False,
+                        self.global_ring_id, True)
                     continue
                 pipeline_endpoints = [
                     self.endpoints[first_node], self.endpoints[second_node]

python/paddle/fluid/optimizer.py

@@ -3856,6 +3856,7 @@ def _insert_allreduce_op(self, op_idx, block):
                     'out_dtype': out_var.dtype,
                     self._op_role_key: self._op_role.Optimize
                 })
+            offset += 1
         return offset
 
     def _create_vars(self, block, ori_block):
@@ -4364,12 +4365,15 @@ def _insert_send_recv(cur_id, prev_id):
                                 'ring_id': ring_id
                             })
                         extra_index_info['index'] += 1
+                        var_shape = list(var.shape)
+                        var_shape[0] = self.micro_batch_size if var_shape[
+                            0] < 0 else var_shape[0]
                         block._insert_op_without_sync(
                             index=index + extra_index_info['index'],
                             type='recv_v2',
                             outputs={'Out': [var]},
                             attrs={
-                                'out_shape': var.shape,
+                                'out_shape': var_shape,
                                 'dtype': var.dtype,
                                 self._op_device_key: cur_dev,
                                 self._op_role_key: op_role,

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

@@ -0,0 +1,159 @@
+#   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import print_function
+
+import numpy as np
+import argparse
+import time
+import math
+
+import paddle
+import paddle.fluid as fluid
+import paddle.fluid.profiler as profiler
+from paddle.fluid import core
+import unittest
+from multiprocessing import Process
+import os
+import signal
+from functools import reduce
+from test_dist_base import TestDistRunnerBase, runtime_main
+import paddle.distributed.fleet as fleet
+
+paddle.enable_static()
+
+DTYPE = "float32"
+paddle.dataset.mnist.fetch()
+
+# Fix seed for test
+fluid.default_startup_program().random_seed = 1
+fluid.default_main_program().random_seed = 1
+
+
+def cnn_model(data):
+    conv_pool_1 = fluid.nets.simple_img_conv_pool(
+        input=data,
+        filter_size=5,
+        num_filters=20,
+        pool_size=2,
+        pool_stride=2,
+        act="relu",
+        param_attr=fluid.ParamAttr(initializer=fluid.initializer.Constant(
+            value=0.01)))
+    conv_pool_2 = fluid.nets.simple_img_conv_pool(
+        input=conv_pool_1,
+        filter_size=5,
+        num_filters=50,
+        pool_size=2,
+        pool_stride=2,
+        act="relu",
+        param_attr=fluid.ParamAttr(initializer=fluid.initializer.Constant(
+            value=0.01)))
+
+    SIZE = 10
+    input_shape = conv_pool_2.shape
+    param_shape = [reduce(lambda a, b: a * b, input_shape[1:], 1)] + [SIZE]
+    scale = (2.0 / (param_shape[0]**2 * SIZE))**0.5
+
+    with fluid.device_guard("gpu:1"):
+        predict = fluid.layers.fc(
+            input=conv_pool_2,
+            size=SIZE,
+            act="softmax",
+            param_attr=fluid.param_attr.ParamAttr(
+                initializer=fluid.initializer.Constant(value=0.01)))
+        # To cover @RENAMED@GRADIENT
+        predict2 = fluid.layers.fc(
+            input=conv_pool_1,
+            size=SIZE,
+            act="softmax",
+            param_attr=fluid.param_attr.ParamAttr(
+                initializer=fluid.initializer.Constant(value=0.01)))
+        predict += predict2
+    return predict
+
+
+class TestDistMnist2x2(TestDistRunnerBase):
+    def get_model(self, batch_size=2, use_dgc=False, dist_strategy=None):
+        # Input data
+        with fluid.device_guard("gpu:0"):
+            images = fluid.layers.data(
+                name='pixel', shape=[1, 28, 28], dtype=DTYPE)
+            label = fluid.layers.data(name='label', shape=[1], dtype='int64')
+
+            if dist_strategy:
+                data_loader = fluid.io.DataLoader.from_generator(
+                    feed_list=[images, label],
+                    capacity=64,
+                    use_double_buffer=False,
+                    iterable=False)
+            # Train program
+            predict = cnn_model(images)
+        with fluid.device_guard("gpu:1"):
+            cost = fluid.layers.cross_entropy(input=predict, label=label)
+            avg_cost = fluid.layers.mean(x=cost)
+
+        # Evaluator
+        with fluid.device_guard("gpu:1"):
+            batch_size_tensor = fluid.layers.create_tensor(dtype='int64')
+            batch_acc = fluid.layers.accuracy(
+                input=predict, label=label, total=batch_size_tensor)
+
+        inference_program = fluid.default_main_program().clone()
+        base_lr = self.lr
+        passes = [30, 60, 80, 90]
+        steps_per_pass = 10
+        bd = [steps_per_pass * p for p in passes]
+        lr = [base_lr * (0.1**i) for i in range(len(bd) + 1)]
+        lr_val = fluid.layers.piecewise_decay(boundaries=bd, values=lr)
+        opt = fluid.optimizer.Momentum(
+            learning_rate=lr_val,
+            momentum=0.9,
+            grad_clip=fluid.clip.GradientClipByGlobalNorm(clip_norm=1.0))
+
+        acc_steps = 2  # accumulated steps for pipeline
+        if dist_strategy:
+            # Reader
+            train_reader = paddle.batch(
+                paddle.dataset.mnist.test(), batch_size=batch_size)
+            test_reader = paddle.batch(
+                paddle.dataset.mnist.test(), batch_size=batch_size)
+            fleet.init(is_collective=True)
+            strategy = fleet.DistributedStrategy()
+            strategy.pipeline = True
+            strategy.amp = True
+            strategy.pipeline_configs = {
+                'micro_batch_size': batch_size,
+                'schedule_mode': 'F-then-B',
+                'accumulate_steps': acc_steps
+            }
+            dist_opt = fleet.distributed_optimizer(
+                optimizer=opt, strategy=strategy)
+            dist_opt.minimize(avg_cost)
+        else:
+            opt.minimize(avg_cost)
+            # Reader
+            train_reader = paddle.batch(
+                paddle.dataset.mnist.test(), batch_size=batch_size * acc_steps)
+            test_reader = paddle.batch(
+                paddle.dataset.mnist.test(), batch_size=batch_size * acc_steps)
+
+        if dist_strategy:
+            return inference_program, avg_cost, train_reader, test_reader, batch_acc, predict, data_loader
+        else:
+            return inference_program, avg_cost, train_reader, test_reader, batch_acc, predict
+
+
+if __name__ == "__main__":
+    runtime_main(TestDistMnist2x2)

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

@@ -44,6 +44,15 @@ def test_dist_train(self):
                 check_error_log=True,
                 log_name=flag_name)
 
+    def test_dist_train_multi_device(self):
+        import paddle.fluid as fluid
+        if fluid.core.is_compiled_with_cuda():
+            self.check_with_place(
+                "pipeline_mnist_multi_device.py",
+                check_error_log=True,
+                delta=1e0,
+                log_name=flag_name)
+
     def test_dist_train_one_device(self):
         import paddle.fluid as fluid
         if fluid.core.is_compiled_with_cuda():