Fuse Convolution and Eltwise Add into MKLDNN's Conv+Bias (#12669)

* Fuse Convolution and Eltwise Add into Conv+Bias

* Reduce bias branching at conv_mkldnn_op

* Add MKLDNN build checks for Conv Bias

* Conv-bias: check if bias input exist befor assignment

* Conv-bias: Remove Bias dim check from infershape

It was causing conv3d test to crash upon\ncalling HasInput(Bias)

paddle/fluid/operators/conv_mkldnn_op.cc

@@ -126,6 +126,15 @@ class ConvMKLDNNHandler : public platform::MKLDNNHandler {
                                pipeline);
   }
 
+  std::shared_ptr<mkldnn::memory> AcquireBiasMemoryFromPrimitive(
+      const std::shared_ptr<mkldnn::memory> user_bias_memory_p,
+      std::vector<mkldnn::primitive>& pipeline) {  // NOLINT
+    auto user_bias_pd = user_bias_memory_p->get_primitive_desc();
+    auto bias_pd = conv_pd_->bias_primitive_desc();
+    return this->AcquireMemory(bias_pd, user_bias_pd, user_bias_memory_p,
+                               "@bias_mem_p", pipeline);
+  }
+
   std::shared_ptr<mkldnn::convolution_forward> AcquireConvolution(
       std::shared_ptr<mkldnn::memory> src_memory_p,
       std::shared_ptr<mkldnn::memory> weights_memory_p,
@@ -147,6 +156,28 @@ class ConvMKLDNNHandler : public platform::MKLDNNHandler {
     return conv_p;
   }
 
+  std::shared_ptr<mkldnn::convolution_forward> AcquireConvolution(
+      std::shared_ptr<mkldnn::memory> src_memory_p,
+      std::shared_ptr<mkldnn::memory> weights_memory_p,
+      std::shared_ptr<mkldnn::memory> bias_memory_p,
+      std::shared_ptr<mkldnn::memory> dst_memory_p) {
+    auto prim_key = key_ + "@conv_p";
+    auto conv_p = std::static_pointer_cast<mkldnn::convolution_forward>(
+        dev_ctx_.GetBlob(prim_key));
+    PADDLE_ENFORCE((conv_p != nullptr) || (is_reusing_ == false),
+                   "Fail to find convolution primitive in device context");
+    if (conv_p == nullptr) {
+      conv_p = std::make_shared<mkldnn::convolution_forward>(
+          *conv_pd_, *(src_memory_p), *(weights_memory_p.get()),
+          *(bias_memory_p.get()), *(dst_memory_p.get()));
+
+      dev_ctx_.SetBlob(prim_key, conv_p);
+    } else {
+      is_reusing_ = true;
+    }
+    return conv_p;
+  }
+
   std::shared_ptr<mkldnn::convolution_backward_weights>
   AcquireConvolutionBackwardWeights(
       std::shared_ptr<mkldnn::memory> src_memory_p,
@@ -229,6 +260,7 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
 
     auto* input = ctx.Input<Tensor>("Input");
     auto* filter = ctx.Input<Tensor>("Filter");
+    auto* bias = ctx.HasInput("Bias") ? ctx.Input<Tensor>("Bias") : nullptr;
     auto* output = ctx.Output<Tensor>("Output");
 
     PADDLE_ENFORCE(input->layout() == DataLayout::kMKLDNN &&
@@ -237,6 +269,17 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
     PADDLE_ENFORCE(filter->layout() == DataLayout::kMKLDNN &&
                        filter->format() != memory::format::format_undef,
                    "Wrong layout/format set for Filter tensor");
+    PADDLE_ENFORCE(input->dims().size() == 4,
+                   "Input must be with 4 dimensions, i.e. NCHW");
+    PADDLE_ENFORCE(filter->dims().size() == 4,
+                   "Filter must be with 4 dimensions, i.e. OIHW");
+    if (bias) {
+      PADDLE_ENFORCE(bias->layout() == DataLayout::kMKLDNN &&
+                         bias->format() != memory::format::format_undef,
+                     "Wrong layout/format set for Bias tensor");
+      PADDLE_ENFORCE(bias->dims().size() == 1,
+                     "Bias must only have 1 dimension, i.e. X");
+    }
 
     std::vector<int> strides = ctx.Attr<std::vector<int>>("strides");
     std::vector<int> paddings = ctx.Attr<std::vector<int>>("paddings");
@@ -253,11 +296,6 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
     const T* filter_data = filter->data<T>();
     T* output_data = output->mutable_data<T>(ctx.GetPlace());
 
-    PADDLE_ENFORCE(input->dims().size() == 4,
-                   "Input must be with 4 dimensions, i.e. NCHW");
-    PADDLE_ENFORCE(filter->dims().size() == 4,
-                   "Filter must be with 4 dimensions, i.e. OIHW");
-
     std::vector<int> src_tz = paddle::framework::vectorize2int(input->dims());
     std::vector<int> weights_tz =
         paddle::framework::vectorize2int(filter->dims());
@@ -288,13 +326,23 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
         src_tz, platform::MKLDNNGetDataType<T>(), chosen_memory_format);
     auto weights_md = platform::MKLDNNMemDesc(
         weights_tz, platform::MKLDNNGetDataType<T>(), chosen_memory_format);
+    std::vector<int> bias_tz;  // TODO(mgallus): avoid empty vector creation.
+                               // Currently used whenever bias is != nullptr.
     auto dst_md = platform::MKLDNNMemDesc(
         dst_tz, platform::MKLDNNGetDataType<T>(), chosen_memory_format);
 
     // create a conv primitive descriptor and save it for usage in backward
-    std::shared_ptr<mkldnn::convolution_forward::primitive_desc> conv_pd =
-        ConvFwdPrimitiveDesc(src_md, weights_md, dst_md, strides, paddings,
-                             mkldnn_engine);
+    std::shared_ptr<mkldnn::convolution_forward::primitive_desc> conv_pd;
+    if (bias) {
+      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);
+    } else {
+      conv_pd = ConvFwdPrimitiveDesc(src_md, weights_md, dst_md, strides,
+                                     paddings, mkldnn_engine);
+    }
     // Save conv_pd/src_memory/weights_memory for backward pass
     dev_ctx.SetBlob(key_conv_pd, conv_pd);
 
@@ -315,8 +363,22 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
         handler.AcquireDstMemoryFromPrimitive(to_void_cast<T>(output_data));
 
     // create convolution op primitive
-    auto conv_p = handler.AcquireConvolution(src_memory_p, weights_memory_p,
+    std::shared_ptr<mkldnn::convolution_forward> conv_p;
+    if (bias) {
+      const T* bias_data = bias->data<T>();
+      auto user_bias_md = platform::MKLDNNMemDesc(
+          {bias_tz}, platform::MKLDNNGetDataType<T>(), memory::format::x);
+      auto user_bias_memory_p =
+          handler.AcquireBiasMemory(user_bias_md, to_void_cast<T>(bias_data));
+
+      auto bias_memory_p =
+          handler.AcquireBiasMemoryFromPrimitive(user_bias_memory_p, pipeline);
+      conv_p = handler.AcquireConvolution(src_memory_p, weights_memory_p,
+                                          bias_memory_p, dst_memory_p);
+    } else {
+      conv_p = handler.AcquireConvolution(src_memory_p, weights_memory_p,
                                           dst_memory_p);
+    }
 
     // push primitive to stream and wait until it's executed
     pipeline.push_back(*conv_p);
@@ -346,6 +408,27 @@ class ConvMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
     return std::unique_ptr<mkldnn::convolution_forward::primitive_desc>(
         p_conv_pd);
   }
+
+  std::unique_ptr<mkldnn::convolution_forward::primitive_desc>
+  ConvFwdPrimitiveDesc(const memory::desc& src, const memory::desc& weights,
+                       const memory::desc& bias, const memory::desc& dst,
+                       const std::vector<int>& strides,
+                       const std::vector<int>& paddings,
+                       const mkldnn::engine& engine) const {
+    memory::dims stride_dims = {strides[0], strides[1]};
+    memory::dims padding_dims = {paddings[0], paddings[1]};
+
+    auto conv_desc = mkldnn::convolution_forward::desc(
+        mkldnn::prop_kind::forward, mkldnn::convolution_direct, src, weights,
+        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);
+
+    return std::unique_ptr<mkldnn::convolution_forward::primitive_desc>(
+        p_conv_pd);
+  }
 };
 
 template <typename T>

paddle/fluid/operators/conv_op.cc

@@ -37,6 +37,7 @@ void ConvOp::InferShape(framework::InferShapeContext* ctx) const {
 
   auto in_dims = ctx->GetInputDim("Input");
   auto filter_dims = ctx->GetInputDim("Filter");
+
   std::vector<int> strides = ctx->Attrs().Get<std::vector<int>>("strides");
   std::vector<int> paddings = ctx->Attrs().Get<std::vector<int>>("paddings");
   int groups = ctx->Attrs().Get<int>("groups");
@@ -57,7 +58,6 @@ void ConvOp::InferShape(framework::InferShapeContext* ctx) const {
   PADDLE_ENFORCE_EQ(in_dims[1], filter_dims[1] * groups,
                     "The number of input channels should be equal to filter "
                     "channels * groups.");
-
   PADDLE_ENFORCE_EQ(
       filter_dims[0] % groups, 0,
       "The number of output channels should be divided by groups.");
@@ -122,6 +122,11 @@ void Conv2DOpMaker::Make() {
            "H is the height of the filter, and W is the width of the filter. "
            "If the groups attribute is greater than 1, C equals the number of "
            "input image channels divided by the groups.");
+  AddInput("Bias",
+           "(Tensor) Bias to be added to each output of filter application."
+           "The format of output tensor is X (one-dimensional) of size equal"
+           "to the number of output channels. Only used with MKL-DNN.")
+      .AsDispensable();
   AddOutput("Output",
             "(Tensor) The output tensor of convolution operator. "
             "The format of output tensor is also NCHW.")

paddle/fluid/platform/mkldnn_helper.h

@@ -125,6 +125,11 @@ class MKLDNNHandler {
     return this->AcquireMemory(md, ptr, "@user_weights_mem_p");
   }
 
+  std::shared_ptr<mkldnn::memory> AcquireBiasMemory(
+      const mkldnn::memory::desc& md, void* ptr) {
+    return this->AcquireMemory(md, ptr, "@user_bias_mem_p");
+  }
+
   std::shared_ptr<mkldnn::memory> AcquireDstMemory(
       const mkldnn::memory::desc& md, void* ptr) {
     return this->AcquireMemory(md, ptr, "@user_dst_mem_p");

python/paddle/fluid/transpiler/inference_transpiler.py

@@ -59,8 +59,12 @@ class InferenceTranspiler(object):
             scope = global_scope()
         if not isinstance(scope, core.Scope):
             raise TypeError("scope should be as Scope type or None")
-        self._fuse_batch_norm(program, place, scope)
+        use_mkldnn = bool(os.getenv("FLAGS_use_mkldnn", False))
+        if use_mkldnn:
             self._fuse_relu_mkldnn(program)
+            self._fuse_conv_bias_mkldnn(program)
+        else:
+            self._fuse_batch_norm(program, place, scope)
 
     def _fuse_relu_mkldnn(self, program):
         '''
@@ -82,10 +86,6 @@ class InferenceTranspiler(object):
         :param program: program to transpile
         :type program: Program
         '''
-        use_mkldnn = bool(os.getenv("FLAGS_use_mkldnn", False))
-        if not use_mkldnn:
-            return
-
         self.block = program.block(0)
 
         i = 0
@@ -106,6 +106,69 @@ class InferenceTranspiler(object):
         # And a better solution will be considered later.
         program = program.clone()
 
+    def _fuse_conv_bias_mkldnn(self, program):
+        '''
+        Transpile the program by fused convolution and elementwise_add.
+
+        Replace conv2d and elementwise_add ops with a new conv2d op
+        based on an old conv2d op and the :math:`Bias` taken from
+        elementwise_add.
+
+        For input :math:`X`:
+
+        - Conv process:            :math:`X = input * W`
+        - Elementwise_add process: :math` X = X + bias`
+
+        After fuse into one operation:
+
+        .. math::
+
+            X = input * W + bias
+
+        The operator transformation is:
+
+        - before:
+
+          - conv->elementwise_add->any_other_op
+
+        - after:
+
+          - conv->any_other_op
+
+        The transpile stages are:
+
+        1. Extract bias and output variables from elementwise_add.
+        2. Extract Input, Weight and attributes from conv op.
+        3. Create a new convolution op based on extracted params.
+        4. Remove old conv op.
+        5. Remove elementwise_add.
+        5. Remove unused variables.
+
+        Args:
+            program (Program): program to transpile
+
+        '''
+        self.block = program.block(0)
+
+        i = 0
+        while i < len(self.block.ops) - 2:
+            current_op = self.block.ops[i]
+            next_op = self.block.ops[i + 1]
+            # conv2d with bias
+            if current_op.type in ['conv2d'] and \
+               next_op.type in ['elementwise_add']:
+                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()
+        # 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_batch_norm(self, program, place, scope):
         '''
         Transpile the program by fused batch normalization.
@@ -185,7 +248,6 @@ class InferenceTranspiler(object):
                         self.block._remove_op(i + 2)
                         i = i + 1
             i = i + 1
-
         self._adjust_input()
         self._remove_unused_var()
         # TODO(luotao): use clone() method to flush the program.desc in force,
@@ -288,6 +350,33 @@ class InferenceTranspiler(object):
         # collect the renamed input
         self.input_map[bn_op.output("Y")[0]] = bias_op.output("Out")[0]
 
+    def _fuse_conv_bias(self, index, conv_op, elementwise_add_op):
+        '''
+        fuse the conv op with elementwise_add
+
+        :param index: index of the conv_op in ops list
+        :type index: Int
+        :param conv_op: convolution operator
+        :type conv_op: Operator
+        :param elementwise_add_op: convolution's bias operator
+        :type elementwise_add_op: Operator
+        '''
+
+        bias_var = self.block.var(elementwise_add_op.input("Y")[0])
+        out_var = self.block.var(elementwise_add_op.output("Out")[0])
+        filter_var = self.block.var(conv_op.input("Filter")[0])
+        in_var = self.block.var(conv_op.input("Input")[0])
+        attrs = {name: conv_op.attr(name) for name in conv_op.attr_names}
+
+        self.block._insert_op(
+            index,
+            type="conv2d",
+            inputs={"Input": in_var,
+                    "Filter": filter_var,
+                    "Bias": bias_var},
+            outputs={"Output": out_var},
+            attrs=attrs)
+
     def _adjust_input(self):
         for i in range(len(self.block.ops)):
             current_op = self.block.ops[i]