CLInstanceNormalizationLayer NHWC optimisation

* Make changes to split the workload into two kernels. One kernel precomputes
  mean and variance and the second kernel just loads these precomputed values.

* The new approach runs %30 faster than the original code for NHWC workloads
  like 32x192x256.

* Resolves MLCE-337

Change-Id: I8356fcefa2d131ab4dcb32268ce7142421d073e4
Signed-off-by: Pablo Marquez Tello <pablo.tello@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/5355
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Manuel Bottini <manuel.bottini@arm.com>
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>

1 files changed, 32 insertions, 5 deletions

diff --git a/arm_compute/runtime/CL/functions/CLInstanceNormalizationLayer.h b/arm_compute/runtime/CL/functions/CLInstanceNormalizationLayer.h
index d41f3fedf6..a6e5b1622b 100644
--- a/arm_compute/runtime/CL/functions/CLInstanceNormalizationLayer.h
+++ b/arm_compute/runtime/CL/functions/CLInstanceNormalizationLayer.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2020 Arm Limited.
+ * Copyright (c) 2019-2021 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -25,24 +25,44 @@
 #define ARM_COMPUTE_CLINSTANCENORMALIZATIONLAYER_H
 
 #include "arm_compute/core/Error.h"
-#include "arm_compute/runtime/CL/ICLSimpleFunction.h"
+#include "arm_compute/runtime/CL/CLTensor.h"
+#include "arm_compute/runtime/IFunction.h"
+
+#include <memory>
 
 namespace arm_compute
 {
 class CLCompileContext;
 class ICLTensor;
 class ITensorInfo;
+class ICLKernel;
+class CLRuntimeContext;
 
 /** Basic function to perform a Instance normalization.
  *
  * This function runs the following kernels:
  * -# @ref CLInstanceNormalizationLayerKernel
  */
-class CLInstanceNormalizationLayer : public ICLSimpleFunction
+class CLInstanceNormalizationLayer : public IFunction
 {
 public:
-    /** Default constructor */
-    CLInstanceNormalizationLayer();
+    /** Constructor
+     *
+     * @param[in] ctx Runtime context to be used by the function
+     */
+    CLInstanceNormalizationLayer(CLRuntimeContext *ctx = nullptr);
+
+    /** Prevent instances of this class from being copied (As this class contains pointers) */
+    CLInstanceNormalizationLayer(const CLInstanceNormalizationLayer &) = delete;
+    /** Default move constructor */
+    CLInstanceNormalizationLayer(CLInstanceNormalizationLayer &&) = default;
+    /** Prevent instances of this class from being copied (As this class contains pointers) */
+    CLInstanceNormalizationLayer &operator=(const CLInstanceNormalizationLayer &) = delete;
+    /** Default move assignment operator */
+    CLInstanceNormalizationLayer &operator=(CLInstanceNormalizationLayer &&) = default;
+    /** Default destructor */
+    ~CLInstanceNormalizationLayer();
+
     /** Set the input and output tensors.
      *
      * @param[in, out] input               Source tensor. In case of @p output tensor = nullptr this tensor will store the result of the normalization.
@@ -79,6 +99,13 @@ public:
      * @return a status
      */
     static Status validate(const ITensorInfo *input, const ITensorInfo *output, float gamma = 1.0f, float beta = 0.0f, float epsilon = 1e-12f, bool use_mixed_precision = true);
+    void run() override;
+
+private:
+    std::unique_ptr<ICLKernel> _inst_norm_kernel; /**< Kernel to run */
+    std::unique_ptr<ICLKernel> _mean_var_kernel;  /**< Kernel to run */
+    CLTensor                   _mean_var_tensor;
+    CLRuntimeContext          *_ctx; /**< Context to use */
 };
 } // namespace arm_compute
 #endif /* ARM_COMPUTE_CLINSTANCENORMALIZATIONLAYER_H */