[1/10] CMSIS-NN graph partitioner for softmax (apache#8653)

* cmsis graph partitioner for softmax

Change-Id: I80ecd7bc5351f241b4674ef53b36e4398c8adb83

* Updated docstring in the partioning function

Change-Id: Ieb4b623e5929cfdb6aa0235db64c825fac8d7055

python/tvm/relay/op/contrib/cmsisnn.py

@@ -0,0 +1,80 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+# pylint: disable=invalid-name, unused-argument
+"""Arm(R) CMSIS-NN supported operators for Cortex-M."""
+import tvm.ir
+from tvm.relay import transform
+from tvm.relay.build_module import bind_params_by_name
+
+from ...dataflow_pattern import is_constant, is_op, wildcard
+from .register import register_pattern_table
+
+
+def partition_for_cmsisnn(mod, params=None, **opts):
+    """Partition the graph greedily offloading supported
+    operators on Cortex-M using CMSIS-NN
+
+    Parameters
+    ----------
+    mod : Module
+        The module to run passes on.
+    params : Optional[Dict[str, NDArray]]
+        Constant input parameters.
+
+    Returns
+    -------
+    ret : Module
+        annotated and partitioned module.
+    """
+    if params:
+        mod["main"] = bind_params_by_name(mod["main"], params)
+
+    seq = tvm.transform.Sequential(
+        [
+            transform.InferType(),
+            transform.MergeComposite(pattern_table()),
+            transform.AnnotateTarget("cmsisnn"),
+            transform.MergeCompilerRegions(),
+            transform.PartitionGraph(),
+        ]
+    )
+
+    return seq(mod)
+
+
+@register_pattern_table("cmsisnn")
+def pattern_table():
+    """Get the cmsisnn compiler pattern table."""
+
+    def softmax_pattern():
+        pattern = is_op("qnn.dequantize")(wildcard(), is_constant(), is_constant())
+        pattern = is_op("nn.softmax")(pattern)
+        pattern = is_op("qnn.quantize")(pattern, is_constant(), is_constant())
+        return pattern
+
+    def check_quantized_softmax(extract):
+        """Check if softmax is supported by CMSIS-NN."""
+
+        # check for dtypes of quantize and dequantize
+        return (
+            extract.attrs.out_dtype == "int8"
+            and extract.args[0].args[0].args[0].checked_type.dtype == "int8"
+        )
+
+    return [
+        ("cmsisnn.qnn_softmax", softmax_pattern(), check_quantized_softmax),
+    ]

tests/python/contrib/test_cmsisnn/test_softmax.py

@@ -0,0 +1,107 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""CMSIS-NN integration tests: softmax"""
+
+import pytest
+import sys
+
+import tvm
+from tvm import relay
+from tvm.relay.op.contrib import cmsisnn
+import numpy as np
+
+
+def count_num_calls(mod):
+    class CallCounter(relay.ExprVisitor):
+        def __init__(self):
+            super().__init__()
+            self.count = 0
+
+        def visit_call(self, call):
+            if isinstance(call.op, tvm.ir.Op):
+                self.count += 1
+
+            super().visit_call(call)
+
+    counter = CallCounter()
+    for var in mod.get_global_vars():
+        counter.visit(mod[var.name_hint])
+    return counter.count
+
+
+def make_module(func):
+    func = relay.Function(relay.analysis.free_vars(func), func)
+    mod = tvm.IRModule.from_expr(func)
+    return relay.transform.InferType()(mod)
+
+
+def make_model(shape, zero_point, scale, in_dtype, out_dtype):
+    a = relay.var("a", shape=shape, dtype=in_dtype)
+    dequantize = relay.qnn.op.dequantize(
+        a,
+        input_scale=relay.const(scale, "float32"),
+        input_zero_point=relay.const(zero_point, "int32"),
+    )
+    softmax = relay.nn.softmax(dequantize)
+    model = relay.qnn.op.quantize(
+        softmax,
+        output_scale=relay.const(scale, "float32"),
+        output_zero_point=relay.const(zero_point, "int32"),
+        out_dtype=out_dtype,
+    )
+    return model
+
+
+def test_softmax_int8():
+    model = make_model([1, 16, 16, 3], 64, 0.02, "int8", "int8")
+    orig_mod = make_module(model)
+    cmsisnn_mod = cmsisnn.partition_for_cmsisnn(orig_mod)
+
+    attrs = [
+        cmsisnn_mod[var.name_hint].attrs
+        for var in cmsisnn_mod.get_global_vars()
+        if cmsisnn_mod[var.name_hint].attrs
+    ]
+    assert any(attrs), "At least one function with external attributes was expected."
+
+    compilers = [
+        key == "Compiler" and value == "cmsisnn" for attr in attrs for key, value in attr.items()
+    ]
+    assert any(compilers), "Module does not contain function for cmsisnn target."
+
+    assert count_num_calls(orig_mod) == count_num_calls(
+        cmsisnn_mod
+    ), "Number of calls changed during partitioning"
+
+
+@pytest.mark.parametrize("in_dtype,out_dtype", [["uint8", "int8"], ["int8", "uint8"]])
+def test_softmax_not_int8(in_dtype, out_dtype):
+    model = make_model([1, 16, 16, 3], 64, 0.02, in_dtype, out_dtype)
+    orig_mod = make_module(model)
+    cmsisnn_mod = cmsisnn.partition_for_cmsisnn(orig_mod)
+
+    attrs = [
+        cmsisnn_mod[var.name_hint].attrs
+        for var in cmsisnn_mod.get_global_vars()
+        if cmsisnn_mod[var.name_hint].attrs
+    ]
+    assert not any(attrs), "No function should have an external attribute."
+
+
+if __name__ == "__main__":
+    sys.exit(pytest.main([__file__] + sys.argv[1:]))