Add precondition comment to process_dump_config_()

Extract the dump_config block (version/chip info logging + per-component
dump_config iteration) into a separate noinline process_dump_config_()
method.

This code runs once at startup and once on API reconnect, but was
inlined into loop() which runs ~7000 times/minute. On ESP32 the
dump_config block compiled to ~140 bytes (38% of loop's 368 bytes),
including esp_chip_info(), integer division for revision formatting,
and multiple ESP_LOG calls. Extracting it frees ~2 icache lines for
the hot path.

esphome/components/api/api_connection.cpp

@@ -219,8 +219,35 @@ void APIConnection::loop() {
     this->process_batch_();
   }
 
-  if (this->active_iterator_ != ActiveIterator::NONE) {
-    this->process_active_iterator_();
+  switch (this->active_iterator_) {
+    case ActiveIterator::LIST_ENTITIES:
+      if (this->iterator_storage_.list_entities.completed()) {
+        this->destroy_active_iterator_();
+        if (this->flags_.state_subscription) {
+          this->begin_iterator_(ActiveIterator::INITIAL_STATE);
+        }
+      } else {
+        this->process_iterator_batch_(this->iterator_storage_.list_entities);
+      }
+      break;
+    case ActiveIterator::INITIAL_STATE:
+      if (this->iterator_storage_.initial_state.completed()) {
+        this->destroy_active_iterator_();
+        // Process any remaining batched messages immediately
+        if (!this->deferred_batch_.empty()) {
+          this->process_batch_();
+        }
+        // Now that everything is sent, enable immediate sending for future state changes
+        this->flags_.should_try_send_immediately = true;
+        // Release excess memory from buffers that grew during initial sync
+        this->deferred_batch_.release_buffer();
+        this->helper_->release_buffers();
+      } else {
+        this->process_iterator_batch_(this->iterator_storage_.initial_state);
+      }
+      break;
+    case ActiveIterator::NONE:
+      break;
   }
 
   if (this->flags_.sent_ping) {
@@ -256,49 +283,6 @@ void APIConnection::loop() {
 #endif
 }
 
-void APIConnection::process_active_iterator_() {
-  // Caller ensures active_iterator_ != NONE
-  if (this->active_iterator_ == ActiveIterator::LIST_ENTITIES) {
-    if (this->iterator_storage_.list_entities.completed()) {
-      this->destroy_active_iterator_();
-      if (this->flags_.state_subscription) {
-        this->begin_iterator_(ActiveIterator::INITIAL_STATE);
-      }
-    } else {
-      this->process_iterator_batch_(this->iterator_storage_.list_entities);
-    }
-  } else {  // INITIAL_STATE
-    if (this->iterator_storage_.initial_state.completed()) {
-      this->destroy_active_iterator_();
-      // Process any remaining batched messages immediately
-      if (!this->deferred_batch_.empty()) {
-        this->process_batch_();
-      }
-      // Now that everything is sent, enable immediate sending for future state changes
-      this->flags_.should_try_send_immediately = true;
-      // Release excess memory from buffers that grew during initial sync
-      this->deferred_batch_.release_buffer();
-      this->helper_->release_buffers();
-    } else {
-      this->process_iterator_batch_(this->iterator_storage_.initial_state);
-    }
-  }
-}
-
-void APIConnection::process_iterator_batch_(ComponentIterator &iterator) {
-  size_t initial_size = this->deferred_batch_.size();
-  size_t max_batch = this->get_max_batch_size_();
-  while (!iterator.completed() && (this->deferred_batch_.size() - initial_size) < max_batch) {
-    iterator.advance();
-  }
-
-  // If the batch is full, process it immediately
-  // Note: iterator.advance() already calls schedule_batch_() via schedule_message_()
-  if (this->deferred_batch_.size() >= max_batch) {
-    this->process_batch_();
-  }
-}
-
 bool APIConnection::send_disconnect_response_() {
   // remote initiated disconnect_client
   // don't close yet, we still need to send the disconnect response

esphome/components/api/api_connection.h

@@ -15,10 +15,6 @@
 #include <limits>
 #include <vector>
 
-namespace esphome {
-class ComponentIterator;
-}  // namespace esphome
-
 namespace esphome::api {
 
 // Keepalive timeout in milliseconds
@@ -368,13 +364,20 @@ class APIConnection final : public APIServerConnectionBase {
     return this->client_supports_api_version(1, 14) ? MAX_INITIAL_PER_BATCH : MAX_INITIAL_PER_BATCH_LEGACY;
   }
 
-  // Process active iterator (list_entities/initial_state) during connection setup.
-  // Extracted from loop() — only runs during initial handshake, NONE in steady state.
-  void __attribute__((noinline)) process_active_iterator_();
+  // Helper method to process multiple entities from an iterator in a batch
+  template<typename Iterator> void process_iterator_batch_(Iterator &iterator) {
+    size_t initial_size = this->deferred_batch_.size();
+    size_t max_batch = this->get_max_batch_size_();
+    while (!iterator.completed() && (this->deferred_batch_.size() - initial_size) < max_batch) {
+      iterator.advance();
+    }
 
-  // Helper method to process multiple entities from an iterator in a batch.
-  // Takes ComponentIterator base class reference to avoid duplicate template instantiations.
-  void process_iterator_batch_(ComponentIterator &iterator);
+    // If the batch is full, process it immediately
+    // Note: iterator.advance() already calls schedule_batch_() via schedule_message_()
+    if (this->deferred_batch_.size() >= max_batch) {
+      this->process_batch_();
+    }
+  }
 
 #ifdef USE_BINARY_SENSOR
   static uint16_t try_send_binary_sensor_state(EntityBase *entity, APIConnection *conn, uint32_t remaining_size);

esphome/components/api/list_entities.h

@@ -94,6 +94,7 @@ class ListEntitiesIterator : public ComponentIterator {
   bool on_update(update::UpdateEntity *entity) override;
 #endif
   bool on_end() override;
+  bool completed() { return this->state_ == IteratorState::NONE; }
 
  protected:
   APIConnection *client_;

esphome/components/api/subscribe_state.h

@@ -88,6 +88,7 @@ class InitialStateIterator : public ComponentIterator {
 #ifdef USE_UPDATE
   bool on_update(update::UpdateEntity *entity) override;
 #endif
+  bool completed() { return this->state_ == IteratorState::NONE; }
 
  protected:
   APIConnection *client_;

esphome/core/application.cpp

@@ -204,36 +204,40 @@ void Application::loop() {
   this->last_loop_ = last_op_end_time;
 
   if (this->dump_config_at_ < this->components_.size()) {
-    if (this->dump_config_at_ == 0) {
-      char build_time_str[Application::BUILD_TIME_STR_SIZE];
-      this->get_build_time_string(build_time_str);
-      ESP_LOGI(TAG, "ESPHome version " ESPHOME_VERSION " compiled on %s", build_time_str);
+    this->process_dump_config_();
+  }
+}
+
+void Application::process_dump_config_() {
+  if (this->dump_config_at_ == 0) {
+    char build_time_str[Application::BUILD_TIME_STR_SIZE];
+    this->get_build_time_string(build_time_str);
+    ESP_LOGI(TAG, "ESPHome version " ESPHOME_VERSION " compiled on %s", build_time_str);
 #ifdef ESPHOME_PROJECT_NAME
-      ESP_LOGI(TAG, "Project " ESPHOME_PROJECT_NAME " version " ESPHOME_PROJECT_VERSION);
+    ESP_LOGI(TAG, "Project " ESPHOME_PROJECT_NAME " version " ESPHOME_PROJECT_VERSION);
 #endif
 #ifdef USE_ESP32
-      esp_chip_info_t chip_info;
-      esp_chip_info(&chip_info);
-      ESP_LOGI(TAG, "ESP32 Chip: %s rev%d.%d, %d core(s)", ESPHOME_VARIANT, chip_info.revision / 100,
-               chip_info.revision % 100, chip_info.cores);
+    esp_chip_info_t chip_info;
+    esp_chip_info(&chip_info);
+    ESP_LOGI(TAG, "ESP32 Chip: %s rev%d.%d, %d core(s)", ESPHOME_VARIANT, chip_info.revision / 100,
+             chip_info.revision % 100, chip_info.cores);
 #if defined(USE_ESP32_VARIANT_ESP32) && !defined(USE_ESP32_MIN_CHIP_REVISION_SET)
-      // Suggest optimization for chips that don't need the PSRAM cache workaround
-      if (chip_info.revision >= 300) {
+    // Suggest optimization for chips that don't need the PSRAM cache workaround
+    if (chip_info.revision >= 300) {
 #ifdef USE_PSRAM
-        ESP_LOGW(TAG, "Set minimum_chip_revision: \"%d.%d\" to save ~10KB IRAM", chip_info.revision / 100,
-                 chip_info.revision % 100);
+      ESP_LOGW(TAG, "Set minimum_chip_revision: \"%d.%d\" to save ~10KB IRAM", chip_info.revision / 100,
+               chip_info.revision % 100);
 #else
-        ESP_LOGW(TAG, "Set minimum_chip_revision: \"%d.%d\" to reduce binary size", chip_info.revision / 100,
-                 chip_info.revision % 100);
-#endif
-      }
-#endif
+      ESP_LOGW(TAG, "Set minimum_chip_revision: \"%d.%d\" to reduce binary size", chip_info.revision / 100,
+               chip_info.revision % 100);
 #endif
     }
-
-    this->components_[this->dump_config_at_]->call_dump_config();
-    this->dump_config_at_++;
+#endif
+#endif
   }
+
+  this->components_[this->dump_config_at_]->call_dump_config();
+  this->dump_config_at_++;
 }
 
 void IRAM_ATTR HOT Application::feed_wdt(uint32_t time) {

esphome/core/application.h

@@ -519,6 +519,11 @@ class Application {
   void before_loop_tasks_(uint32_t loop_start_time);
   void after_loop_tasks_();
 
+  /// Process dump_config output one component per loop iteration.
+  /// Extracted from loop() to keep cold startup/reconnect logging out of the hot path.
+  /// Caller must ensure dump_config_at_ < components_.size().
+  void __attribute__((noinline)) process_dump_config_();
+
   void feed_wdt_arch_();
 
   /// Perform a delay while also monitoring socket file descriptors for readiness

esphome/core/component_iterator.h

@@ -26,7 +26,6 @@ class ComponentIterator {
  public:
   void begin(bool include_internal = false);
   void advance();
-  bool completed() const { return this->state_ == IteratorState::NONE; }
   virtual bool on_begin();
 #ifdef USE_BINARY_SENSOR
   virtual bool on_binary_sensor(binary_sensor::BinarySensor *binary_sensor) = 0;