Add TensorBuffer::GetAllocatedBytes() method.

We now call `Tensor::AllocatedBytes()` for every tensor fed into and fetched from a session. The current implementation incurs protobuf overhead to create the requisite AllocationDescription, then typically falls back to `Tensor::TotalBytes()` anyway.

PiperOrigin-RevId: 266933172

tensorflow/core/framework/tensor.cc

@@ -66,6 +66,17 @@ namespace tensorflow {
 // code).
 REGISTER_UNARY_VARIANT_DECODE_FUNCTION(Tensor, "tensorflow::Tensor");
 
+bool TensorBuffer::GetAllocatedBytes(size_t* out_bytes) const {
+  AllocationDescription allocation_description;
+  FillAllocationDescription(&allocation_description);
+  if (allocation_description.allocated_bytes() > 0) {
+    *out_bytes = allocation_description.allocated_bytes();
+    return true;
+  } else {
+    return false;
+  }
+}
+
 namespace {
 
 // An un-templated base class for Buffer.
@@ -75,6 +86,16 @@ class BufferBase : public TensorBuffer {
       : TensorBuffer(data_ptr), alloc_(alloc) {}
 
   TensorBuffer* root_buffer() override { return this; }
+
+  bool GetAllocatedBytes(size_t* out_bytes) const override {
+    if (alloc_->TracksAllocationSizes()) {
+      *out_bytes = alloc_->AllocatedSize(data());
+      return *out_bytes > 0;
+    } else {
+      return false;
+    }
+  }
+
   void FillAllocationDescription(AllocationDescription* proto) const override {
     void* data_ptr = data();
     int64 rb = size();
@@ -784,6 +805,13 @@ static Allocator* get_default_cpu_allocator() {
 Tensor::Tensor(DataType type, const TensorShape& shape)
     : Tensor(get_default_cpu_allocator(), type, shape) {}
 
+bool Tensor::HostScalarTensorBufferBase::GetAllocatedBytes(
+    size_t* out_bytes) const {
+  // `this->FillAllocationDescription()` never sets allocated bytes information,
+  // so we can short-circuit the construction of an `AllocationDescription`.
+  return false;
+}
+
 void Tensor::HostScalarTensorBufferBase::FillAllocationDescription(
     AllocationDescription* proto) const {
   proto->set_requested_bytes(size());
@@ -811,6 +839,9 @@ class SubBuffer : public TensorBuffer {
 
   size_t size() const override { return sizeof(T) * elem_; }
   TensorBuffer* root_buffer() override { return root_; }
+  bool GetAllocatedBytes(size_t* out_bytes) const override {
+    return root_->GetAllocatedBytes(out_bytes);
+  }
   void FillAllocationDescription(AllocationDescription* proto) const override {
     root_->FillAllocationDescription(proto);
   }
@@ -937,15 +968,13 @@ size_t Tensor::TotalBytes() const {
 }
 
 size_t Tensor::AllocatedBytes() const {
-  TensorDescription tensor_description;
-  FillDescription(&tensor_description);
-  if (tensor_description.has_allocation_description() &&
-      tensor_description.allocation_description().allocated_bytes() > 0) {
-    return tensor_description.allocation_description().allocated_bytes();
-  } else {
-    // Fall back to TotalBytes() if the allocator doesn't have its size.
-    return TotalBytes();
+  if (buf_) {
+    size_t ret;
+    if (buf_->GetAllocatedBytes(&ret)) {
+      return ret;
+    }
   }
+  return TotalBytes();
 }
 
 bool Tensor::CanUseDMA() const {

tensorflow/core/framework/tensor.h

@@ -79,6 +79,8 @@ class TensorBuffer : public core::RefCounted {
   virtual void FillAllocationDescription(
       AllocationDescription* proto) const = 0;
 
+  virtual bool GetAllocatedBytes(size_t* out_bytes) const;
+
   /// \brief Helper method to reinterpret the buffer as an array of `T`.
   template <typename T>
   T* base() const {
@@ -940,6 +942,7 @@ inline Tensor::Tensor(Tensor&& other)
 class Tensor::HostScalarTensorBufferBase : public TensorBuffer {
  public:
   using TensorBuffer::TensorBuffer;
+  bool GetAllocatedBytes(size_t* out_bytes) const final;
   void FillAllocationDescription(AllocationDescription* proto) const final;
 };
 
@@ -950,7 +953,8 @@ template <typename T>
 struct Tensor::ValueAndTensorBuffer {
   class HostScalarTensorBuffer : public Tensor::HostScalarTensorBufferBase {
    public:
-    HostScalarTensorBuffer(void* data) : HostScalarTensorBufferBase(data) {}
+    explicit HostScalarTensorBuffer(void* data)
+        : HostScalarTensorBufferBase(data) {}
     size_t size() const final { return sizeof(T); }
     TensorBuffer* root_buffer() final { return this; }