Fuse MKLDNN's Conv + ReLU

paddle/fluid/operators/conv_mkldnn_op.cc

@@ -296,6 +296,7 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
     std::vector<int> strides = ctx.Attr<std::vector<int>>("strides");
     std::vector<int> paddings = ctx.Attr<std::vector<int>>("paddings");
     std::vector<int> dilations = ctx.Attr<std::vector<int>>("dilations");
+    bool fuse_relu = ctx.Attr<bool>("fuse_relu");
     int groups = ctx.Attr<int>("groups");
 
     // TODO(pzelazko-intel) add support for group convolution and dilation
@@ -348,11 +349,12 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
       bias_tz = paddle::framework::vectorize2int(bias->dims());
       auto bias_md = platform::MKLDNNMemDesc(
           bias_tz, platform::MKLDNNGetDataType<T>(), memory::format::x);
-      conv_pd = ConvFwdPrimitiveDesc(src_md, weights_md, bias_md, dst_md,
-                                     strides, paddings, mkldnn_engine);
+      conv_pd =
+          ConvFwdPrimitiveDesc(src_md, weights_md, bias_md, dst_md, strides,
+                               paddings, mkldnn_engine, fuse_relu);
     } else {
       conv_pd = ConvFwdPrimitiveDesc(src_md, weights_md, dst_md, strides,
-                                     paddings, mkldnn_engine);
+                                     paddings, mkldnn_engine, fuse_relu);
     }
     // Save conv_pd/src_memory/weights_memory for backward pass
     dev_ctx.SetBlob(key_conv_pd, conv_pd);
@@ -402,11 +404,26 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
   }
 
  private:
+  mkldnn::primitive_attr AddRelu() const {
+    // Fusion with ReLU layer is executed through the PostOps feature. Create a
+    // PostOps object and configure it to execute an eltwise relu operation.
+    mkldnn::primitive_attr conv_attr;
+    constexpr float scale = 1.0f;
+    constexpr float negative_slope = 0.0f;
+    constexpr float placeholder = 0.0f;
+    mkldnn::post_ops post_operations;
+    post_operations.append_eltwise(scale, mkldnn::algorithm::eltwise_relu,
+                                   negative_slope, placeholder);
+    conv_attr.set_post_ops(post_operations);
+    return conv_attr;
+  }
+
   std::unique_ptr<mkldnn::convolution_forward::primitive_desc>
   ConvFwdPrimitiveDesc(const memory::desc& src, const memory::desc& weights,
                        const memory::desc& dst, const std::vector<int>& strides,
                        const std::vector<int>& paddings,
-                       const mkldnn::engine& engine) const {
+                       const mkldnn::engine& engine,
+                       const bool fuse_relu) const {
     memory::dims stride_dims = {strides[0], strides[1]};
     memory::dims padding_dims = {paddings[0], paddings[1]};
 
@@ -415,8 +432,13 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
         dst, stride_dims, padding_dims, padding_dims,
         mkldnn::padding_kind::zero);
 
-    auto p_conv_pd =
-        new mkldnn::convolution_forward::primitive_desc(conv_desc, engine);
+    mkldnn::primitive_attr conv_attr;
+    if (fuse_relu) {
+      conv_attr = AddRelu();
+    }
+
+    auto p_conv_pd = new mkldnn::convolution_forward::primitive_desc(
+        conv_desc, conv_attr, engine);
 
     return std::unique_ptr<mkldnn::convolution_forward::primitive_desc>(
         p_conv_pd);
@@ -427,7 +449,8 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
                        const memory::desc& bias, const memory::desc& dst,
                        const std::vector<int>& strides,
                        const std::vector<int>& paddings,
-                       const mkldnn::engine& engine) const {
+                       const mkldnn::engine& engine,
+                       const bool fuse_relu) const {
     memory::dims stride_dims = {strides[0], strides[1]};
     memory::dims padding_dims = {paddings[0], paddings[1]};
 
@@ -436,8 +459,13 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
         bias, dst, stride_dims, padding_dims, padding_dims,
         mkldnn::padding_kind::zero);
 
-    auto p_conv_pd =
-        new mkldnn::convolution_forward::primitive_desc(conv_desc, engine);
+    mkldnn::primitive_attr conv_attr;
+    if (fuse_relu) {
+      conv_attr = AddRelu();
+    }
+
+    auto p_conv_pd = new mkldnn::convolution_forward::primitive_desc(
+        conv_desc, conv_attr, engine);
 
     return std::unique_ptr<mkldnn::convolution_forward::primitive_desc>(
         p_conv_pd);

paddle/fluid/operators/conv_op.cc

@@ -161,6 +161,8 @@ void Conv2DOpMaker::Make() {
   AddAttr<bool>("use_mkldnn",
                 "(bool, default false) Only used in mkldnn kernel")
       .SetDefault(false);
+  AddAttr<bool>("fuse_relu", "(bool, default false) Only used in mkldnn kernel")
+      .SetDefault(false);
   AddAttr<std::string>(
       "data_format",
       "(string, default NCHW) Only used in "

python/paddle/fluid/transpiler/inference_transpiler.py

@@ -60,12 +60,46 @@ class InferenceTranspiler(object):
         if not isinstance(scope, core.Scope):
             raise TypeError("scope should be as Scope type or None")
         use_mkldnn = bool(os.getenv("FLAGS_use_mkldnn", False))
+
         self._fuse_batch_norm(program, place, scope)
         if use_mkldnn:
-            self._fuse_relu_mkldnn(program)
             self._fuse_conv_bias_mkldnn(program)
+            self._fuse_conv_relu_mkldnn(program)
+            self._fuse_bn_relu_mkldnn(program)
+
+    def _fuse_conv_relu_mkldnn(self, program):
+        '''
+        Transpile the program by fused relu activation for MKLDNN program.
+        Relu activation following convolution OP can be fused by adding
+        'fuse_relu' attribute to convolution OP.
+        The result of fuse is:
+            - before:
+                - conv->relu->any_other_op
+            - after:
+                - conv->any_other_op
+        :param program: program to transpile
+        :type program: Program
+        '''
+        self.block = program.block(0)
+
+        i = 0
+        while i < len(self.block.ops):
+            current_op = self.block.ops[i]
+            if current_op.type in ['conv2d']:
+                next_op = self.block.ops[i + 1]
+                if next_op.type == 'relu':
+                    # modify conv OP to include relu
+                    current_op.set_attr("fuse_relu", True)
+                    # remove conv OP
+                    self.block._remove_op(i + 1)
+            i = i + 1
+
+        # TODO(luotao): use clone() method to flush the program.desc in force,
+        # since some large program.desc will not be flushed immediately.
+        # And a better solution will be considered later.
+        program = program.clone()
 
-    def _fuse_relu_mkldnn(self, program):
+    def _fuse_bn_relu_mkldnn(self, program):
         '''
         Transpile the program by fused relu activation for MKLDNN program.
 
@@ -159,7 +193,6 @@ class InferenceTranspiler(object):
                 self._fuse_conv_bias(i, current_op, next_op)
                 self.block._remove_op(i + 1)  # Remove old conv
                 self.block._remove_op(i + 1)  # Remove elementwise_add
-                i = i + 1
             i = i + 1
 
         self._remove_unused_var()