Skip empty eager reset pipelines

Keep reset masks canonical while using one explicit host predicate to avoid dispatching every reset manager for an empty selection. This recovers the eager hot path until recorded reset launches can remove the boundary.

Author: hujc7

source/isaaclab_experimental/isaaclab_experimental/envs/manager_based_rl_env_warp.py

@@ -580,6 +580,12 @@ def _reset_idx(
     def _reset_terminated_envs(self) -> None:
         """Reset terminated environments, compacting IDs only for host consumers."""
         reset_mask = self.termination_manager.dones_wp
+        # The eager reset pipeline contains many small launches. Keep the mask as
+        # the canonical selection, but use one explicit host predicate to avoid
+        # dispatching the entire pipeline when it is empty. Record/replay can
+        # remove this boundary once reset stages have replay-safe launch caches.
+        if not self.reset_buf.any().item():
+            return
         reset_env_ids = None
         if self._reset_requires_host_selection():
             with Timer(

source/isaaclab_experimental/test/envs/test_manager_based_rl_env_warp.py

@@ -190,3 +190,19 @@ def test_empty_reset_skips_legacy_host_boundary_and_preserves_logs() -> None:
     env._reset_host_pre.assert_not_called()
     env._reset_host_post.assert_not_called()
     assert env.extras["log"] == {"previous": 1.0}
+
+
+def test_empty_reset_skips_warp_pipeline_without_compacting_ids() -> None:
+    """An empty mask should skip eager reset stages without materializing IDs."""
+    env = ManagerBasedRLEnvWarp.__new__(ManagerBasedRLEnvWarp)
+    reset_mask = wp.zeros(3, dtype=wp.bool, device="cpu")
+    env.termination_manager = SimpleNamespace(dones_wp=reset_mask)
+    env.reset_buf = torch.zeros(3, dtype=torch.bool)
+    env._reset_requires_host_selection = Mock(return_value=False)
+    env._reset_idx = Mock()
+    env.extras = {"log": {"previous": 1.0}}
+
+    env._reset_terminated_envs()
+
+    env._reset_idx.assert_not_called()
+    assert env.extras["log"] == {"previous": 1.0}