Add world-size getter in Engine

deepspeed/runtime/engine.py

@@ -748,6 +748,10 @@ def get_tensor_parallel_rank(self):
     def get_model_parallel_rank(self):
         return groups.get_model_parallel_rank()
 
+    def get_parallel_world_sizes(self):
+        """Return a dict of parallel world sizes for data/tensor parallelism."""
+        return {"dp": groups.get_data_parallel_world_size(), "tp": groups.get_tensor_model_parallel_world_size()}
+
     def get_sequence_parallel_group(self):
         return self.seq_parallel_group
 

deepspeed/runtime/pipe/engine.py

@@ -537,6 +537,12 @@ def is_last_stage(self):
     def get_pipeline_parallel_rank(self):
         return self.stage_id
 
+    def get_parallel_world_sizes(self):
+        """Return a dict of parallel world sizes for data/tensor/pipeline parallelism."""
+        sizes = super().get_parallel_world_sizes()
+        sizes["pp"] = self.num_stages
+        return sizes
+
     def _reduce_outputs(self, outputs, reduce='avg', reduce_dp=True, micro_batches=None):
         if reduce is None:
             return outputs

tests/unit/runtime/test_parallel_info.py

@@ -0,0 +1,54 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0
+
+# DeepSpeed Team
+
+import pytest
+from deepspeed.runtime.engine import DeepSpeedEngine
+from deepspeed.runtime.pipe.engine import PipelineEngine
+
+
+# Silence destructors because instances are created via __new__ (no init)
+@pytest.fixture(autouse=True)
+def _silence_engine_destructors(monkeypatch):
+    monkeypatch.setattr(DeepSpeedEngine, "__del__", lambda self: None, raising=False)
+    monkeypatch.setattr(PipelineEngine, "__del__", lambda self: None, raising=False)
+    monkeypatch.setattr(DeepSpeedEngine, "destroy", lambda self: None, raising=False)
+    monkeypatch.setattr(PipelineEngine, "destroy", lambda self: None, raising=False)
+
+
+# Skip if methods are absent (e.g., running against an older DS build)
+if (not hasattr(DeepSpeedEngine, "get_parallel_world_sizes")
+        or not hasattr(PipelineEngine, "get_parallel_world_sizes")):
+    pytest.skip("Required methods missing on this DeepSpeed build.", allow_module_level=True)
+
+
+def _patch_groups(monkeypatch, dp=8, tp=4):
+    """Patch deepspeed.utils.groups to avoid initializing any distributed backend."""
+    import deepspeed.utils.groups as groups
+    monkeypatch.setattr(groups, "get_data_parallel_world_size", lambda: dp, raising=True)
+    monkeypatch.setattr(groups, "get_tensor_model_parallel_world_size", lambda: tp, raising=True)
+
+
+def _make_engine():
+    """Create engine without running __init__ to avoid side effects."""
+    return DeepSpeedEngine.__new__(DeepSpeedEngine)
+
+
+def _make_pipeline_engine(num_stages=6):
+    """Create pipeline engine without init; set the minimal required attribute."""
+    pe = PipelineEngine.__new__(PipelineEngine)
+    pe.num_stages = num_stages
+    return pe
+
+
+def test_deepspeedengine_get_parallel_world_sizes(monkeypatch):
+    _patch_groups(monkeypatch, dp=8, tp=4)
+    eng = _make_engine()
+    assert eng.get_parallel_world_sizes() == {"dp": 8, "tp": 4}
+
+
+def test_pipelineengine_get_parallel_world_sizes(monkeypatch):
+    _patch_groups(monkeypatch, dp=8, tp=4)
+    peng = _make_pipeline_engine(num_stages=6)
+    assert peng.get_parallel_world_sizes() == {"dp": 8, "tp": 4, "pp": 6}