[core] Add CodSpeed C++ benchmarks for protobuf, main loop, and helpers (#14878)

tests/benchmarks/components/api/bench_proto_encode.cpp

@@ -0,0 +1,298 @@
+#include <benchmark/benchmark.h>
+
+#include "esphome/components/api/api_pb2.h"
+#include "esphome/components/api/api_buffer.h"
+
+namespace esphome::api::benchmarks {
+
+// Inner iteration count to amortize CodSpeed instrumentation overhead.
+// Without this, the ~60ns per-iteration valgrind start/stop cost dominates
+// sub-microsecond benchmarks.
+static constexpr int kInnerIterations = 2000;
+
+// --- SensorStateResponse (highest frequency message) ---
+
+static void Encode_SensorStateResponse(benchmark::State &state) {
+  APIBuffer buffer;
+  SensorStateResponse msg;
+  msg.key = 0x12345678;
+  msg.state = 23.5f;
+  msg.missing_state = false;
+  uint32_t size = msg.calculate_size();
+  buffer.resize(size);
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      ProtoWriteBuffer writer(&buffer, 0);
+      msg.encode(writer);
+    }
+    benchmark::DoNotOptimize(buffer.data());
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(Encode_SensorStateResponse);
+
+static void CalculateSize_SensorStateResponse(benchmark::State &state) {
+  SensorStateResponse msg;
+  msg.key = 0x12345678;
+  msg.state = 23.5f;
+  msg.missing_state = false;
+
+  for (auto _ : state) {
+    uint32_t result = 0;
+    for (int i = 0; i < kInnerIterations; i++) {
+      result += msg.calculate_size();
+    }
+    benchmark::DoNotOptimize(result);
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(CalculateSize_SensorStateResponse);
+
+// Steady state: buffer already allocated from previous iteration
+static void CalcAndEncode_SensorStateResponse(benchmark::State &state) {
+  APIBuffer buffer;
+  SensorStateResponse msg;
+  msg.key = 0x12345678;
+  msg.state = 23.5f;
+  msg.missing_state = false;
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      uint32_t size = msg.calculate_size();
+      buffer.resize(size);
+      ProtoWriteBuffer writer(&buffer, 0);
+      msg.encode(writer);
+    }
+    benchmark::DoNotOptimize(buffer.data());
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(CalcAndEncode_SensorStateResponse);
+
+// Cold path: fresh buffer each iteration (measures heap allocation cost).
+// Inner loop still needed to amortize CodSpeed instrumentation overhead.
+// Each inner iteration creates a fresh buffer, so this measures
+// alloc+calc+encode per item.
+static void CalcAndEncode_SensorStateResponse_Fresh(benchmark::State &state) {
+  SensorStateResponse msg;
+  msg.key = 0x12345678;
+  msg.state = 23.5f;
+  msg.missing_state = false;
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      APIBuffer buffer;
+      uint32_t size = msg.calculate_size();
+      buffer.resize(size);
+      ProtoWriteBuffer writer(&buffer, 0);
+      msg.encode(writer);
+      benchmark::DoNotOptimize(buffer.data());
+    }
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(CalcAndEncode_SensorStateResponse_Fresh);
+
+// --- BinarySensorStateResponse ---
+
+static void Encode_BinarySensorStateResponse(benchmark::State &state) {
+  APIBuffer buffer;
+  BinarySensorStateResponse msg;
+  msg.key = 0xAABBCCDD;
+  msg.state = true;
+  msg.missing_state = false;
+  uint32_t size = msg.calculate_size();
+  buffer.resize(size);
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      ProtoWriteBuffer writer(&buffer, 0);
+      msg.encode(writer);
+    }
+    benchmark::DoNotOptimize(buffer.data());
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(Encode_BinarySensorStateResponse);
+
+// --- HelloResponse (string fields) ---
+
+static void Encode_HelloResponse(benchmark::State &state) {
+  APIBuffer buffer;
+  HelloResponse msg;
+  msg.api_version_major = 1;
+  msg.api_version_minor = 10;
+  msg.server_info = StringRef::from_lit("esphome v2026.3.0");
+  msg.name = StringRef::from_lit("living-room-sensor");
+  uint32_t size = msg.calculate_size();
+  buffer.resize(size);
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      ProtoWriteBuffer writer(&buffer, 0);
+      msg.encode(writer);
+    }
+    benchmark::DoNotOptimize(buffer.data());
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(Encode_HelloResponse);
+
+// --- LightStateResponse (complex multi-field message) ---
+
+static void Encode_LightStateResponse(benchmark::State &state) {
+  APIBuffer buffer;
+  LightStateResponse msg;
+  msg.key = 0x11223344;
+  msg.state = true;
+  msg.brightness = 0.8f;
+  msg.color_mode = enums::COLOR_MODE_RGB_WHITE;
+  msg.color_brightness = 1.0f;
+  msg.red = 1.0f;
+  msg.green = 0.5f;
+  msg.blue = 0.2f;
+  msg.white = 0.0f;
+  msg.color_temperature = 4000.0f;
+  msg.cold_white = 0.0f;
+  msg.warm_white = 0.0f;
+  msg.effect = StringRef::from_lit("rainbow");
+  uint32_t size = msg.calculate_size();
+  buffer.resize(size);
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      ProtoWriteBuffer writer(&buffer, 0);
+      msg.encode(writer);
+    }
+    benchmark::DoNotOptimize(buffer.data());
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(Encode_LightStateResponse);
+
+static void CalculateSize_LightStateResponse(benchmark::State &state) {
+  LightStateResponse msg;
+  msg.key = 0x11223344;
+  msg.state = true;
+  msg.brightness = 0.8f;
+  msg.color_mode = enums::COLOR_MODE_RGB_WHITE;
+  msg.color_brightness = 1.0f;
+  msg.red = 1.0f;
+  msg.green = 0.5f;
+  msg.blue = 0.2f;
+  msg.white = 0.0f;
+  msg.color_temperature = 4000.0f;
+  msg.cold_white = 0.0f;
+  msg.warm_white = 0.0f;
+  msg.effect = StringRef::from_lit("rainbow");
+
+  for (auto _ : state) {
+    uint32_t result = 0;
+    for (int i = 0; i < kInnerIterations; i++) {
+      result += msg.calculate_size();
+    }
+    benchmark::DoNotOptimize(result);
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(CalculateSize_LightStateResponse);
+
+// --- DeviceInfoResponse (nested submessages: 20 devices + 20 areas) ---
+
+static DeviceInfoResponse make_device_info_response() {
+  DeviceInfoResponse msg;
+  msg.name = StringRef::from_lit("living-room-sensor");
+  msg.mac_address = StringRef::from_lit("AA:BB:CC:DD:EE:FF");
+  msg.esphome_version = StringRef::from_lit("2026.3.0");
+  msg.compilation_time = StringRef::from_lit("Mar 16 2026, 12:00:00");
+  msg.model = StringRef::from_lit("esp32-poe-iso");
+  msg.manufacturer = StringRef::from_lit("Olimex");
+  msg.friendly_name = StringRef::from_lit("Living Room Sensor");
+#ifdef USE_DEVICES
+  for (uint32_t i = 0; i < ESPHOME_DEVICE_COUNT && i < 20; i++) {
+    msg.devices[i].device_id = i + 1;
+    msg.devices[i].name = StringRef::from_lit("device");
+    msg.devices[i].area_id = (i % 20) + 1;
+  }
+#endif
+#ifdef USE_AREAS
+  for (uint32_t i = 0; i < ESPHOME_AREA_COUNT && i < 20; i++) {
+    msg.areas[i].area_id = i + 1;
+    msg.areas[i].name = StringRef::from_lit("area");
+  }
+#endif
+  return msg;
+}
+
+static void CalculateSize_DeviceInfoResponse(benchmark::State &state) {
+  auto msg = make_device_info_response();
+
+  for (auto _ : state) {
+    uint32_t result = 0;
+    for (int i = 0; i < kInnerIterations; i++) {
+      result += msg.calculate_size();
+    }
+    benchmark::DoNotOptimize(result);
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(CalculateSize_DeviceInfoResponse);
+
+static void Encode_DeviceInfoResponse(benchmark::State &state) {
+  auto msg = make_device_info_response();
+  APIBuffer buffer;
+  uint32_t total_size = msg.calculate_size();
+  buffer.resize(total_size);
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      ProtoWriteBuffer writer(&buffer, 0);
+      msg.encode(writer);
+    }
+    benchmark::DoNotOptimize(buffer.data());
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(Encode_DeviceInfoResponse);
+
+// Steady state: buffer already allocated from previous iteration
+static void CalcAndEncode_DeviceInfoResponse(benchmark::State &state) {
+  auto msg = make_device_info_response();
+  APIBuffer buffer;
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      uint32_t size = msg.calculate_size();
+      buffer.resize(size);
+      ProtoWriteBuffer writer(&buffer, 0);
+      msg.encode(writer);
+    }
+    benchmark::DoNotOptimize(buffer.data());
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(CalcAndEncode_DeviceInfoResponse);
+
+// Cold path: fresh buffer each iteration (measures heap allocation cost).
+// Inner loop still needed to amortize CodSpeed instrumentation overhead.
+// Each inner iteration creates a fresh buffer, so this measures
+// alloc+calc+encode per item.
+static void CalcAndEncode_DeviceInfoResponse_Fresh(benchmark::State &state) {
+  auto msg = make_device_info_response();
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      APIBuffer buffer;
+      uint32_t size = msg.calculate_size();
+      buffer.resize(size);
+      ProtoWriteBuffer writer(&buffer, 0);
+      msg.encode(writer);
+      benchmark::DoNotOptimize(buffer.data());
+    }
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(CalcAndEncode_DeviceInfoResponse_Fresh);
+
+}  // namespace esphome::api::benchmarks