[device] find best logical mesh

tests/test_device/test_extract_alpha_beta.py

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+from functools import partial
+
+import pytest
+import torch.multiprocessing as mp
+
+from colossalai.device import AlphaBetaProfiler
+from colossalai.initialize import launch
+from colossalai.logging import disable_existing_loggers
+from colossalai.testing import parameterize, rerun_if_address_is_in_use
+from colossalai.utils import free_port
+
+
+def check_extract_alpha_beta(rank, physical_devices, world_size, port):
+    disable_existing_loggers()
+    launch(config={}, rank=rank, world_size=world_size, host='localhost', port=port, backend='nccl')
+    profiler = AlphaBetaProfiler(physical_devices)
+
+    mesh_alpha, mesh_beta = profiler.extract_alpha_beta_for_device_mesh()
+    for alpha in mesh_alpha:
+        assert alpha > 0 and alpha < 1e-3
+    for beta in mesh_beta:
+        assert beta > 0 and beta < 1e-10
+
+
+@pytest.mark.skip(reason="Skip because assertion may fail for CI devices")
+@pytest.mark.dist
+@parameterize('physical_devices', [[0, 1, 2, 3], [0, 3]])
+@rerun_if_address_is_in_use()
+def test_profile_alpha_beta(physical_devices):
+    world_size = 4
+    run_func = partial(check_extract_alpha_beta,
+                       physical_devices=physical_devices,
+                       world_size=world_size,
+                       port=free_port())
+    mp.spawn(run_func, nprocs=world_size)
+
+
+if __name__ == '__main__':
+    test_profile_alpha_beta()