Rough cut, control flow should work for scaleout testing

apex/amp/_process_optimizer.py

@@ -217,6 +217,55 @@ def post_backward_no_master_weights(self, scaler):
         post_backward_models_are_masters(scaler, params, stashed_grads)
 
 
+def prepare_backward_with_master_weights_fused(self, scaler):
+    stash = self._amp_stash
+
+    if not stash.lazy_init_called:
+        self._lazy_init_maybe_master_weights()
+        stash.lazy_init_called = True
+
+
+def post_backward_with_master_weights_fused(self, scaler):
+    stash = self._amp_stash
+    stash.scale = scaler.loss_scale()
+    stash.grads = [[param.grad.data for param in group] for group in self.fp16_groups]
+    stash.output_params = [[param for param in in group] for group in self.fp16_groups]
+
+    norm_groups = []
+    skip = False
+    for grad_group in stash.grads:
+        norm = multi_tensor_applier(
+            stash.multi_tensor_l2norm,
+            stash.dummy_overflow_buf,
+            [grad_group])
+        # Still syncing here for now.
+        norm = float(norm)
+        norm_groups.append(norm)
+        if norm == float('inf') or norm == -float('inf') or norm != norm:
+            skip = True
+    if skip:
+        scaler._overflow_buf.fill_(1.)
+        scaler._has_overflow = True
+
+    self._amp_stash.grad_norms = norm_groups
+
+
+def prepare_backward_no_master_weights_fused(self, scaler):
+    stash = self._amp_stash
+
+    if not stash.lazy_init_called:
+        self._lazy_init_maybe_master_weights()
+        stash.lazy_init_called = True
+
+
+def post_backward_no_master_weights_fused(self, scaler):
+    stash = self._amp_stash
+    stash.scale = scaler.loss_scale()
+    stash.grads = None
+    stash.output_params = None
+    stash.grad_norms = None
+
+
 def _master_params_to_model_params(self):
     stash = self._amp_stash
     if multi_tensor_applier.available:
@@ -252,6 +301,7 @@ def _process_optimizer(optimizer, properties):
     if multi_tensor_applier.available:
         import amp_C
         optimizer._amp_stash.multi_tensor_scale = amp_C.multi_tensor_scale
+        optimizer._amp_stash.multi_tensor_l2norm = amp_C.multi_tensor_l2norm
         optimizer._amp_stash.dummy_overflow_buf = torch.cuda.IntTensor([0]);
 
     if properties.master_weights:
@@ -261,10 +311,10 @@ def _process_optimizer(optimizer, properties):
         optimizer._master_params_to_model_params = types.MethodType(
             _master_params_to_model_params, optimizer)
 
-        if not isinstance(optimizer, FusedAdam):
         old_step = optimizer.step
         def new_step(self):
             retval = old_step()
+            if not isinstance(self, FusedAdam):
                 self._master_params_to_model_params()
             # Clear the master grads that wouldn't be zeroed by model.zero_grad()
             for param in self._amp_stash.all_fp32_from_fp16_params:

apex/optimizers/fused_adam.py

@@ -78,6 +78,11 @@ class FusedAdam(torch.optim.Optimizer):
         if closure is not None:
             loss = closure()
 
+        grads = self._amp_stash.grads
+        output_params = self._amp_stash.output_params
+        scale = self._amp_stash.scale
+        grad_norms = self._amp_stash.grad_norms
+
         if grads is None:
             grads_group = [None]*len(self.param_groups)
         # backward compatibility