enable cudagraph for AUCMetricComputation (#2951)

Summary:
Pull Request resolved: #2951

Previously, enable cudagraph leads to [errors](https://fb.workplace.com/groups/1075192433118967/permalink/1661777797793758/) on AUCMetricComputation.

The root cause is that model forward output tensors `predictions`, `labels`, `weights`, and `grouping_keys`
 got overwritten by the next CUDAGraph replay. This diff fixes the issue by clone these tensors before they are overwritten. The overhead should be small since these tensors only have shape `(n_task, n_examples)`.

Reviewed By: iamzainhuda, TroyGarden

Differential Revision: D74293458

Author: BoyuanFeng

torchrec/metrics/metric_module.py

@@ -370,6 +370,7 @@ def _generate_rec_metrics(
             kwargs = metric_def.arguments
 
         kwargs["enable_pt2_compile"] = metrics_config.enable_pt2_compile
+        kwargs["should_clone_update_inputs"] = metrics_config.should_clone_update_inputs
 
         rec_tasks: List[RecTaskInfo] = []
         if metric_def.rec_tasks and metric_def.rec_task_indices:

torchrec/metrics/metrics_config.py

@@ -170,6 +170,8 @@ class MetricsConfig:
             update if the inputs are invalid. Invalid inputs include the case where all
             examples have 0 weights for a batch.
         enable_pt2_compile (bool): whether to enable PT2 compilation for metrics.
+        should_clone_update_inputs (bool): whether to clone the inputs of update(). This
+            prevents CUDAGraph error on overwritting tensor outputs by subsequent runs.
     """
 
     rec_tasks: List[RecTaskInfo] = field(default_factory=list)
@@ -184,6 +186,7 @@ class MetricsConfig:
     compute_on_all_ranks: bool = False
     should_validate_update: bool = False
     enable_pt2_compile: bool = False
+    should_clone_update_inputs: bool = False
 
 
 DefaultTaskInfo = RecTaskInfo(

torchrec/metrics/rec_metric.py

@@ -384,6 +384,14 @@ def __init__(
         if "enable_pt2_compile" in kwargs:
             del kwargs["enable_pt2_compile"]
 
+        # pyre-fixme[8]: Attribute has type `bool`; used as `Union[bool,
+        #  Dict[str, Any]]`.
+        self._should_clone_update_inputs: bool = kwargs.get(
+            "should_clone_update_inputs", False
+        )
+        if "should_clone_update_inputs" in kwargs:
+            del kwargs["should_clone_update_inputs"]
+
         if self._window_size < self._batch_size:
             raise ValueError(
                 f"Local window size must be larger than batch size. Got local window size {self._window_size} and batch size {self._batch_size}."
@@ -541,6 +549,35 @@ def _create_default_weights(self, predictions: torch.Tensor) -> torch.Tensor:
     def _check_nonempty_weights(self, weights: torch.Tensor) -> torch.Tensor:
         return torch.gt(torch.count_nonzero(weights, dim=-1), 0)
 
+    def clone_update_inputs(
+        self,
+        predictions: RecModelOutput,
+        labels: RecModelOutput,
+        weights: Optional[RecModelOutput],
+        **kwargs: Dict[str, Any],
+    ) -> tuple[
+        RecModelOutput, RecModelOutput, Optional[RecModelOutput], Dict[str, Any]
+    ]:
+        def clone_rec_model_output(
+            rec_model_output: RecModelOutput,
+        ) -> RecModelOutput:
+            if isinstance(rec_model_output, torch.Tensor):
+                return rec_model_output.clone()
+            else:
+                return {k: v.clone() for k, v in rec_model_output.items()}
+
+        predictions = clone_rec_model_output(predictions)
+        labels = clone_rec_model_output(labels)
+        if weights is not None:
+            weights = clone_rec_model_output(weights)
+
+        if "required_inputs" in kwargs:
+            kwargs["required_inputs"] = {
+                k: v.clone() for k, v in kwargs["required_inputs"].items()
+            }
+
+        return predictions, labels, weights, kwargs
+
     def _update(
         self,
         *,
@@ -550,6 +587,11 @@ def _update(
         **kwargs: Dict[str, Any],
     ) -> None:
         with torch.no_grad():
+            if self._should_clone_update_inputs:
+                predictions, labels, weights, kwargs = self.clone_update_inputs(
+                    predictions, labels, weights, **kwargs
+                )
+
             if self._compute_mode in [
                 RecComputeMode.FUSED_TASKS_COMPUTATION,
                 RecComputeMode.FUSED_TASKS_AND_STATES_COMPUTATION,