Arm backend: Add Arm Neural Statistics

backends/arm/CMakeLists.txt

@@ -184,6 +184,36 @@ if(EXECUTORCH_BUILD_VGF)
       set(LIBVGF_PATH "${_vgf_site_pure}")
     endif()
 
+    if(EXECUTORCH_BUILD_TESTS)
+      add_executable(
+        vgf_neural_statistics_test
+        ${EXECUTORCH_ROOT}/backends/arm/test/vgf_neural_statistics_test.cpp
+        ${EXECUTORCH_ROOT}/backends/arm/runtime/VGFNeuralStatistics.cpp
+      )
+      target_include_directories(
+        vgf_neural_statistics_test
+        PRIVATE ${_common_include_directories} ${VULKAN_HEADERS_PATH}
+                ${VOLK_HEADERS_PATH}
+      )
+      target_compile_options(
+        vgf_neural_statistics_test PRIVATE -DUSE_VULKAN_WRAPPER
+                                           -DUSE_VULKAN_VOLK
+      )
+      target_link_libraries(vgf_neural_statistics_test PRIVATE executorch_core)
+      if(TARGET GTest::gtest_main)
+        target_link_libraries(
+          vgf_neural_statistics_test PRIVATE GTest::gtest_main
+        )
+      else()
+        target_link_libraries(
+          vgf_neural_statistics_test PRIVATE gtest gtest_main
+        )
+      endif()
+      add_test(NAME vgf_neural_statistics_test
+               COMMAND vgf_neural_statistics_test
+      )
+    endif()
+
     set(LIBVGF_STATIC "${LIBVGF_PATH}/lib/libvgf.a")
   endif()
 
@@ -194,8 +224,9 @@ if(EXECUTORCH_BUILD_VGF)
   target_include_directories(vgf INTERFACE "${LIBVGF_INCLUDE}")
 
   # Add backend delegate for VGF
-  set(_vgf_backend_sources backends/arm/runtime/VGFBackend.cpp
-                           backends/arm/runtime/VGFSetup.cpp
+  set(_vgf_backend_sources
+      backends/arm/runtime/VGFBackend.cpp backends/arm/runtime/VGFSetup.cpp
+      backends/arm/runtime/VGFNeuralStatistics.cpp
   )
   if(NOT EXECUTORCH_BUILD_VULKAN)
     list(APPEND _vgf_backend_sources backends/vulkan/third-party/volk/volk.c)

backends/arm/runtime/VGFBackend.cpp

@@ -6,8 +6,11 @@
  */
 
 #include <cinttypes>
+#include <cstdlib>
+#include <cstring>
 #include <list>
 #include <numeric>
+#include <string>
 
 using namespace std;
 
@@ -101,6 +104,17 @@ void vkml_free_basics(
   //  vkDestroyInstance(*instance, nullptr);
 }
 
+bool vgf_neural_statistics_profiling_enabled() {
+  const char* value = std::getenv("EXECUTORCH_VGF_ENABLE_NEURAL_STATISTICS");
+  if (value == nullptr || value[0] == '\0') {
+    return false;
+  }
+
+  return std::strcmp(value, "0") != 0 && std::strcmp(value, "false") != 0 &&
+      std::strcmp(value, "FALSE") != 0 && std::strcmp(value, "off") != 0 &&
+      std::strcmp(value, "OFF") != 0;
+}
+
 class VGFBackend final : public ::executorch::runtime::BackendInterface {
  public:
   VGFBackend() = default;
@@ -365,6 +379,28 @@ class VGFBackend final : public ::executorch::runtime::BackendInterface {
 #ifdef ET_EVENT_TRACER_ENABLED
     event_tracer_end_profiling_delegate(event_tracer, dispatch_event);
 
+    if (event_tracer != nullptr && vgf_neural_statistics_profiling_enabled()) {
+      // We attach the neural statistics JSON blob to ETDump as delegate
+      // metadata, when event tracer is active.
+
+      // This is “synthetic” event, which we use as a carrier for metadata
+      EventTracerEntry neural_statistics_event =
+          event_tracer_start_profiling_delegate(
+              event_tracer,
+              kVgfNeuralStatisticsDelegateEventName,
+              /*delegate_debug_id=*/-1);
+
+      // Ask VGF representation for neural accelerator diagnostics
+      std::string neural_statistics_metadata =
+          repr->collect_neural_statistics_metadata();
+
+      event_tracer_end_profiling_delegate(
+          event_tracer,
+          neural_statistics_event,
+          neural_statistics_metadata.data(),
+          neural_statistics_metadata.size());
+    }
+
     EventTracerEntry copy_outputs_event = event_tracer_start_profiling_delegate(
         event_tracer,
         "VGF_COPY_OUTPUTS",