feat(mge/traced_module): add optimization api

GitOrigin-RevId: eaa7402640

imperative/python/megengine/traced_module/__init__.py

@@ -8,6 +8,7 @@
 
 from ..core._imperative_rt.core2 import set_cpp_apply_module_trace
 from . import compat
+from ._passes import optimize
 from .traced_module import (
     TracedModule,
     _register_all_builtin_module,
@@ -19,3 +20,11 @@ from .traced_module import (
 
 _register_all_builtin_module()
 set_cpp_apply_module_trace(cpp_apply_module_trace)
+
+__all__ = {
+    "register_as_builtin",
+    "trace_module",
+    "wrap",
+    "TracedModule",
+    "optimize",
+}

imperative/python/megengine/traced_module/_passes/__init__.py

@@ -0,0 +1,12 @@
+# MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+#
+# Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+
+from . import const_pass, fold_scale_pass, fuse_pass
+from .optimization import optimize
+
+__all__ = ["optimize"]

imperative/python/megengine/traced_module/_passes/optimization.py

@@ -0,0 +1,70 @@
+# MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+#
+# Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+
+from copy import deepcopy
+from typing import List, Set
+
+from ...logger import get_logger
+from ..traced_module import TracedModule
+from .pass_base import get_default_pass_context, get_registered_pass
+
+logger = get_logger(__name__)
+
+
+def optimize(
+    module: TracedModule, enabled_pass: List[str] = ["FuseConvBn"],
+) -> TracedModule:
+    r"""Performs a set of optimization passes to optimize a `TracedModule` for inference.
+
+    The following passes are currently supported:
+
+        * FuseConvBn: fuse BN layers into to conv2d
+        * FuseAddMul: fold adjacent const add or mul binary operations
+        * BackwardFoldScale: backward fold const scaling into weights of conv2d
+
+    Args:
+        module: the :class:`TracedModule` to be optimized.
+        enabled_pass: optimization passes to be enabled during optimization.
+            Default: ["FuseConvBn"]
+
+    Returns:
+        the optimized :class:`TracedModule`.
+    """
+
+    defalut_passes_list = [
+        "FuseConvBn",
+        "FuseAddMul",
+    ]
+
+    if isinstance(enabled_pass, str):
+        enabled_pass = [enabled_pass]
+
+    if "BackwardFoldScale" in enabled_pass:
+        if "FuseConvBn" not in enabled_pass:
+            logger.warning(
+                "Since BackwardFoldScale requires FuseConvBn"
+                ", FuseConvBn will be enabled."
+            )
+            enabled_pass.append("FuseConvBn")
+        defalut_passes_list.extend(
+            ["BackwardFoldScale", "FuseAddMul",]
+        )
+
+    pass_ctx = get_default_pass_context()
+
+    def run_pass(mod: TracedModule):
+        for pass_name in defalut_passes_list:
+            if pass_name in enabled_pass:
+                pass_func = get_registered_pass(pass_name)()
+                mod = pass_func(mod, pass_ctx)
+        return mod
+
+    module = deepcopy(module)
+    module = run_pass(module)
+
+    return module

imperative/python/test/unit/traced_module/test_passes.py

@@ -0,0 +1,106 @@
+# MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+#
+# Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+
+import types
+
+import numpy as np
+import pytest
+
+import megengine as mge
+import megengine.functional as F
+import megengine.module as M
+import megengine.traced_module as tm
+
+
+class myconv(M.Conv2d):
+    pass
+
+
+class mybn(M.BatchNorm2d):
+    pass
+
+
+class MyBlock(M.Module):
+    def __init__(self, conv_cls, bn_cls):
+        super().__init__()
+        self.conv = conv_cls(3, 3, 1, 1, 0)
+        self.bn = bn_cls(3)
+        self.conv2 = conv_cls(3, 3, 1, 1, 0)
+        self.bn2 = bn_cls(3)
+        self.scale = mge.Tensor([3, 4])
+
+    def forward(self, x):
+        x1 = self.conv(x)
+        x1 = self.bn(x1)
+        x1 = F.relu(x1)
+        x1 = x1 * self.scale[0]
+        x2 = self.conv2(x)
+        x2 = self.bn2(x2)
+        x2 = F.relu(x2)
+        x2 = x2 * self.scale[1]
+        y = x1 + x2
+        y = y + 4
+        y = self.scale[0] + y
+        y = F.relu(y) * 3
+        return y
+
+
+class MyModule(M.Module):
+    def __init__(self, conv_cls, bn_cls):
+        super().__init__()
+        self.block_0 = MyBlock(conv_cls, bn_cls)
+        self.block_1 = MyBlock(conv_cls, bn_cls)
+
+    def forward(self, x):
+        x1 = self.block_0(x)
+        x2 = self.block_1(x)
+        y = x1 + x2
+        y = F.reshape(y, (-1))
+        y = y * 3
+        return y
+
+
+@pytest.mark.parametrize("conv_cls", [M.Conv2d, myconv])
+@pytest.mark.parametrize("bn_cls", [M.BatchNorm2d, mybn])
+def test_backward_fold_scale(conv_cls, bn_cls):
+    module = MyModule(conv_cls, bn_cls)
+    module.eval()
+    inp = mge.Tensor(np.random.random((1, 3, 32, 32)))
+    desired = module(inp)
+    traced_net = tm.trace_module(module, inp)
+
+    traced_net = traced_net.flatten()
+    optimized_net = tm.optimize(traced_net, "BackwardFoldScale")
+
+    actual = optimized_net(inp)
+    np.testing.assert_allclose(desired=desired, actual=actual, atol=1e-4)
+    # fuse all mul to conv
+    mul_list = optimized_net.graph.get_method_by_type("__mul__").as_list()
+    assert len(mul_list) == 0
+
+
+@pytest.mark.parametrize("conv_cls", [M.Conv2d, myconv])
+@pytest.mark.parametrize("bn_cls", [M.BatchNorm2d, mybn])
+def test_fuse_bn(conv_cls, bn_cls):
+    module = MyModule(conv_cls, bn_cls)
+    module.eval()
+    inp = mge.Tensor(np.random.random((1, 3, 32, 32)))
+    desired = module(inp)
+    traced_net = tm.trace_module(module, inp)
+
+    traced_net = traced_net.flatten()
+    optimized_net = tm.optimize(traced_net, "FuseConvBn")
+
+    actual = optimized_net(inp)
+    np.testing.assert_allclose(desired=desired, actual=actual, atol=1e-4)
+    # fuse all mul to conv
+    bn_list = optimized_net.graph.get_function_by_type(F.batch_norm).as_list()
+    assert len(bn_list) == 0
+
+    bn_list = optimized_net.graph.get_module_by_type(M.BatchNorm2d).as_list()
+    assert len(bn_list) == 0