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Diffstat (limited to 'tensorflow/contrib/lite/simple_memory_arena.h')
-rw-r--r-- | tensorflow/contrib/lite/simple_memory_arena.h | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/tensorflow/contrib/lite/simple_memory_arena.h b/tensorflow/contrib/lite/simple_memory_arena.h new file mode 100644 index 0000000000..0d0b7f9ff7 --- /dev/null +++ b/tensorflow/contrib/lite/simple_memory_arena.h @@ -0,0 +1,84 @@ +/* Copyright 2017 The TensorFlow Authors. All Rights Reserved. + +Licensed 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. +==============================================================================*/ +#ifndef THIRD_PARTY_TENSORFLOW_CONTRIB_LITE_SIMPLE_MEMORY_ARENA_H_ +#define THIRD_PARTY_TENSORFLOW_CONTRIB_LITE_SIMPLE_MEMORY_ARENA_H_ + +#include <list> +#include <memory> +#include "tensorflow/contrib/lite/context.h" + +namespace tflite { + +// This little structure holds the offset and the size for a dynamic memory +// allocation in the memory arena. When the arena is commited and the +// underlying buffer is set, the alloc can be resolved into an actual memory +// pointer. +struct ArenaAlloc { + ArenaAlloc() : offset(0), size(0) {} + + size_t offset; + size_t size; + + inline bool operator<(const ArenaAlloc& other) const { + return offset < other.offset; + } +}; + +// This small class is responsible for allocating, dealocating and reusing +// dynamic memory from a common underlying buffer. The arena can be used in +// scenarios when the pattern of memory allocations and dealocations is +// repetitive, e.g. running NN inference in multiple iterations. +class SimpleMemoryArena { + public: + explicit SimpleMemoryArena(size_t arena_alignment) + : commited_(false), + arena_alignment_(arena_alignment), + high_water_mark_(0), + underlying_buffer_size_(0), + allocs_() {} + + TfLiteStatus Allocate(TfLiteContext* context, size_t alignment, size_t size, + ArenaAlloc* new_alloc); + + TfLiteStatus Deallocate(TfLiteContext* context, const ArenaAlloc& alloc); + + inline size_t RequiredBufferSize() { + // Add in a small amount of padding to reduce the chance of resize events + // for small allocations. + size_t padding = arena_alignment_; + return arena_alignment_ + high_water_mark_ + padding; + } + + TfLiteStatus Commit(TfLiteContext* context); + + TfLiteStatus ResolveAlloc(TfLiteContext* context, const ArenaAlloc& alloc, + char** output_ptr); + + TfLiteStatus Clear(); + + private: + bool commited_; + size_t arena_alignment_; + size_t high_water_mark_; + std::unique_ptr<char[]> underlying_buffer_; + size_t underlying_buffer_size_; + char* underlying_buffer_aligned_ptr_; + // TODO(maciekc): add list iterator to the ArenaAlloc to lookup quickly. + std::list<ArenaAlloc> allocs_; +}; + +} // namespace tflite + +#endif // THIRD_PARTY_TENSORFLOW_CONTRIB_LITE_SIMPLE_MEMORY_ARENA_H_ |