[benchmark] Add SubscribeLogsResponse encode benchmarks (#15696)

tests/benchmarks/components/api/bench_log_response.cpp

@@ -0,0 +1,118 @@
+#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.
+static constexpr int kInnerIterations = 2000;
+
+// Typical log line: "[12:34:56][D][sensor:094]: 'Temperature': Sending state 23.50000 with 1 decimals of accuracy"
+static constexpr const char *kTypicalLogLine =
+    "[12:34:56][D][sensor:094]: 'Temperature': Sending state 23.50000 with 1 decimals of accuracy";
+
+// Short log line: "[12:34:56][I][app:029]: Running..."
+static constexpr const char *kShortLogLine = "[12:34:56][I][app:029]: Running...";
+
+// --- Encode ---
+
+static void Encode_LogResponse_Typical(benchmark::State &state) {
+  APIBuffer buffer;
+  SubscribeLogsResponse msg;
+  msg.level = enums::LOG_LEVEL_DEBUG;
+  msg.set_message(reinterpret_cast<const uint8_t *>(kTypicalLogLine), strlen(kTypicalLogLine));
+  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_LogResponse_Typical);
+
+static void Encode_LogResponse_Short(benchmark::State &state) {
+  APIBuffer buffer;
+  SubscribeLogsResponse msg;
+  msg.level = enums::LOG_LEVEL_INFO;
+  msg.set_message(reinterpret_cast<const uint8_t *>(kShortLogLine), strlen(kShortLogLine));
+  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_LogResponse_Short);
+
+// --- Calculate Size ---
+
+static void CalculateSize_LogResponse_Typical(benchmark::State &state) {
+  SubscribeLogsResponse msg;
+  msg.level = enums::LOG_LEVEL_DEBUG;
+  msg.set_message(reinterpret_cast<const uint8_t *>(kTypicalLogLine), strlen(kTypicalLogLine));
+
+  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_LogResponse_Typical);
+
+// --- Calc + Encode (steady state) ---
+
+static void CalcAndEncode_LogResponse_Typical(benchmark::State &state) {
+  APIBuffer buffer;
+  SubscribeLogsResponse msg;
+  msg.level = enums::LOG_LEVEL_DEBUG;
+  msg.set_message(reinterpret_cast<const uint8_t *>(kTypicalLogLine), strlen(kTypicalLogLine));
+
+  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_LogResponse_Typical);
+
+// --- Calc + Encode (fresh allocation each time) ---
+
+static void CalcAndEncode_LogResponse_Typical_Fresh(benchmark::State &state) {
+  SubscribeLogsResponse msg;
+  msg.level = enums::LOG_LEVEL_DEBUG;
+  msg.set_message(reinterpret_cast<const uint8_t *>(kTypicalLogLine), strlen(kTypicalLogLine));
+
+  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_LogResponse_Typical_Fresh);
+
+}  // namespace esphome::api::benchmarks