Update on "[ET-VK] Store unique ptr to Tensor in Value instead of inlined tensor object, to reduce Value struct size from 448 to 80 bytes."

This diff aims to reduce the size of the Value struct in the Executorch Vulkan runtime by storing a unique pointer to the Tensor object instead of an inlined tensor object. This change reduces the size of the Value struct from 448 bytes to 80 bytes, which can improve performance and reduce memory usage.

Differential Revision: [D66655991](https://our.internmc.facebook.com/intern/diff/D66655991/)

[ghstack-poisoned]

Author: trivedivivek

backends/vulkan/runtime/graph/containers/Value.h

@@ -117,8 +117,7 @@ struct Value final {
       CASE_MOVE_TRIVIALLY_COPYABLE_TYPE(TypeTag::INT, as_int);
       CASE_MOVE_TRIVIALLY_COPYABLE_TYPE(TypeTag::DOUBLE, as_double);
       CASE_MOVE_TRIVIALLY_COPYABLE_TYPE(TypeTag::BOOL, as_bool);
-      // Tensor and tensor adjacent types
-      CASE_MOVE_UNIQUE_PTR_TYPE(TypeTag::TENSOR, as_tensor);
+      // Tensor adjacent types
       CASE_MOVE_MOVEABLE_TYPE(
           TypeTag::STAGING, api::StagingBuffer, as_staging, StagingBuffer);
       CASE_MOVE_MOVEABLE_TYPE(
@@ -136,6 +135,8 @@ struct Value final {
       CASE_MOVE_MOVEABLE_TYPE(
           TypeTag::STRING, std::string, as_string, basic_string);
       CASE_MOVE_MOVEABLE_TYPE(TypeTag::SYMINT, SymInt, as_symint, SymInt);
+      // Tensor type
+      CASE_MOVE_UNIQUE_PTR_TYPE(TypeTag::TENSOR, as_tensor);
 
       case TypeTag::NONE:
         clearToNone();
@@ -162,9 +163,6 @@ struct Value final {
 
   ~Value() {
     switch (tag) {
-      case TypeTag::TENSOR:
-        payload.as_tensor.reset();
-        break;
       case TypeTag::STAGING:
         payload.as_staging.~StagingBuffer();
         break;
@@ -196,6 +194,9 @@ struct Value final {
       case TypeTag::DOUBLE:
       case TypeTag::BOOL:
         break;
+      case TypeTag::TENSOR:
+        payload.as_tensor.reset();
+        break;
     }
   }
 
@@ -232,39 +233,6 @@ struct Value final {
 
 #undef SUPPORT_TRIVIALLY_COPYABLE_TYPE
 
-#define SUPPORT_TRIVIALLY_MOVEABLE_UNIQUE_PTR_TYPE(             \
-    type, type_name, type_tag, member_name)                     \
-  explicit Value(type t) : tag(type_tag) {                      \
-    payload.member_name = std::make_unique<type>(std::move(t)); \
-  }                                                             \
-  inline bool is##type_name() const {                           \
-    return tag == type_tag;                                     \
-  }                                                             \
-  inline type& to##type_name() const {                          \
-    VK_CHECK_COND(                                              \
-        is##type_name(),                                        \
-        "Expected value to have type " #type_name ", got ",     \
-        tag,                                                    \
-        " instead.");                                           \
-    return *payload.member_name;                                \
-  }                                                             \
-  inline const type& toConst##type_name() const {               \
-    VK_CHECK_COND(                                              \
-        is##type_name(),                                        \
-        "Expected value to have type " #type_name ", got ",     \
-        tag,                                                    \
-        " instead.");                                           \
-    return *payload.member_name;                                \
-  }
-
-  SUPPORT_TRIVIALLY_MOVEABLE_UNIQUE_PTR_TYPE(
-      api::vTensor,
-      Tensor,
-      TypeTag::TENSOR,
-      as_tensor);
-
-#undef SUPPORT_TRIVIALLY_MOVEABLE_UNIQUE_PTR_TYPE
-
 #define SUPPORT_TRIVIALLY_MOVEABLE_TYPE(                    \
     type, type_name, type_tag, member_name)                 \
   explicit Value(type&& t) : tag(type_tag) {                \
@@ -334,9 +302,36 @@ struct Value final {
 
   SUPPORT_TRIVIALLY_MOVEABLE_TYPE(SymInt, SymInt, TypeTag::SYMINT, as_symint);
 
-#undef SUPPORT_TRIVIALLY_COPYABLE_TYPE
 #undef SUPPORT_TRIVIALLY_MOVEABLE_TYPE
 
+#define SUPPORT_UNIQUE_PTR_TYPE(type, type_name, type_tag, member_name) \
+  explicit Value(type t) : tag(type_tag) {                              \
+    payload.member_name = std::make_unique<type>(std::move(t));         \
+  }                                                                     \
+  inline bool is##type_name() const {                                   \
+    return tag == type_tag;                                             \
+  }                                                                     \
+  inline type& to##type_name() const {                                  \
+    VK_CHECK_COND(                                                      \
+        is##type_name(),                                                \
+        "Expected value to have type " #type_name ", got ",             \
+        tag,                                                            \
+        " instead.");                                                   \
+    return *payload.member_name;                                        \
+  }                                                                     \
+  inline const type& toConst##type_name() const {                       \
+    VK_CHECK_COND(                                                      \
+        is##type_name(),                                                \
+        "Expected value to have type " #type_name ", got ",             \
+        tag,                                                            \
+        " instead.");                                                   \
+    return *payload.member_name;                                        \
+  }
+
+  SUPPORT_UNIQUE_PTR_TYPE(api::vTensor, Tensor, TypeTag::TENSOR, as_tensor);
+
+#undef SUPPORT_UNIQUE_PTR_TYPE
+
  private:
   Payload payload;
   TypeTag tag;

backends/vulkan/test/vulkan_compute_api_test.cpp

@@ -1087,8 +1087,8 @@ TEST_F(VulkanComputeAPITest, print_object_sizes) {
 
   // Current known size on 64 bit system: 1040 B
   EXPECT_TRUE(sizeof(vTensor) < 1200);
-  // Current known size on 64 bit system: 1056 B
-  EXPECT_TRUE(sizeof(Value) < 1200);
+  // Current known size on 64 bit system: 80 B
+  EXPECT_TRUE(sizeof(Value) < 88);
   // Current known size on 64 bit system: 120 B
   EXPECT_TRUE(sizeof(StagingBuffer) < 500);
   // Current known size on 64 bit system: 384 B