From 8ffcc7c85cd4538314bf3159dd8d37ba75d80e17 Mon Sep 17 00:00:00 2001
From: ShenLiang <1422485404@qq.com>
Date: Thu, 14 Oct 2021 10:57:24 +0800
Subject: [PATCH] [HybridParallel]Rebuild code for pipeline (#36396)

* add no_sync for parameters sync

* add pipeline for moe
---
 .../fleet/meta_parallel/pipeline_parallel.py  | 55 +++++++++++--------
 python/paddle/fluid/dygraph/parallel.py       | 10 +++-
 2 files changed, 40 insertions(+), 25 deletions(-)

diff --git a/python/paddle/distributed/fleet/meta_parallel/pipeline_parallel.py b/python/paddle/distributed/fleet/meta_parallel/pipeline_parallel.py
index 431bc6d7bc3..90960973972 100755
--- a/python/paddle/distributed/fleet/meta_parallel/pipeline_parallel.py
+++ b/python/paddle/distributed/fleet/meta_parallel/pipeline_parallel.py
@@ -77,26 +77,15 @@ class PipelineParallel(MetaParallelBase):
             logger.info("start broadcast dp parameters")
             broadcast_dp_parameters(self._layers, self._hcg)
 
-    def train_batch(self, data, optimizer, lr_scheduler=None, scaler=None):
-        assert isinstance(optimizer, HybridParallelOptimizer), (
-            'optimizer should be HybridParallelOptimizer subclass.')
-
-        assert fluid.framework._dygraph_tracer()._has_grad, (
-            'Please enable the generation of gradients.')
-
-        if self.is_first_stage or self.is_last_stage:
-            assert data is not None, (
-                "For the first and the last stage, the data must be set.")
-        else:
-            data = None
+    def forward_backward_pipeline(self, data, scaler=None):
+        # use the 1f1b scheduling strategy.
+        # this strategy is inspired by:
+        # https://github.com/NVIDIA/Megatron-LM/blob/main/megatron/schedules.py
 
-        self.optimizer = optimizer
-        self.lr_scheduler = lr_scheduler
         self.scaler = scaler
-        self.data = data
-        self._compute_loss = True
 
-        self._layers.train()
+        # store data for train
+        self.data = data
 
         # store total loss of entire batch
         self.total_loss = None
@@ -104,10 +93,6 @@ class PipelineParallel(MetaParallelBase):
         # store data id for micro_batch
         self.micro_batch_id = 0
 
-        # Next, use the 1f1b scheduling strategy.
-        # this strategy is inspired by:
-        # https://github.com/NVIDIA/Megatron-LM/blob/main/megatron/schedules.py
-
         startup_steps = (self.num_stages - self.stage_id - 1)
         startup_steps = min(startup_steps, self.accumulate_steps)
         steady_steps = self.accumulate_steps - startup_steps
@@ -161,11 +146,35 @@ class PipelineParallel(MetaParallelBase):
 
         self._layers.allreduce_shared_weight_gradients()
 
-        self.train_loss = self._broadcast_final_loss()
+        train_loss = self._broadcast_final_loss()
+
+        return train_loss
+
+    def train_batch(self, data, optimizer, lr_scheduler=None, scaler=None):
+        assert isinstance(optimizer, HybridParallelOptimizer), (
+            'optimizer should be HybridParallelOptimizer subclass.')
+
+        assert fluid.framework._dygraph_tracer()._has_grad, (
+            'Please enable the generation of gradients.')
+
+        if self.is_first_stage or self.is_last_stage:
+            assert data is not None, (
+                "For the first and the last stage, the data must be set.")
+        else:
+            data = None
+
+        self.optimizer = optimizer
+        self.lr_scheduler = lr_scheduler
+
+        self._layers.train()
+
+        # 1f1b for pipeline
+        train_loss = self.forward_backward_pipeline(data, scaler)
 
         # optimizer
         self._optimizer_step()
-        return self.train_loss
+
+        return train_loss
 
     def eval_batch(self, data, compute_loss=False):
         self._layers.eval()
diff --git a/python/paddle/fluid/dygraph/parallel.py b/python/paddle/fluid/dygraph/parallel.py
index e4525a8d179..7dd8d38aa70 100644
--- a/python/paddle/fluid/dygraph/parallel.py
+++ b/python/paddle/fluid/dygraph/parallel.py
@@ -354,9 +354,15 @@ def sync_params_buffers(model,
         if not isinstance(param, core.VarBase):
             raise TypeError("The data type of '%s' must be Varbase" %
                             param.name)
+
         # is_distributed param not need to sync when in mp mode
-        if is_model_parallel and isinstance(param, ParamBase):
-            if param.is_distributed:
+        if isinstance(param, ParamBase):
+            if is_model_parallel and param.is_distributed:
+                continue
+
+            # NOTE(shenliang03): Support situations that do not require synchronization parameters, 
+            # such as moe's expert parameters
+            if getattr(param, "no_sync", False):
                 continue
 
         model_vars.append(param.detach())
-- 
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