Add __attribute__((optimize("O2"))) to the main loop functions
(loop_task on ESP32, codegen loop() on other platforms) so GCC
inlines scheduler helpers and loop bookkeeping more aggressively.
Under -Os, GCC outlines small functions (Scheduler::call helpers,
millis conversions, etc.) that are called every loop iteration.
With -O2, these get inlined into the loop body, reducing call
overhead on the hottest code path in the firmware.
ESP32: loop_task grows from 303 to 416 bytes (+113 bytes).
ESP8266: no change (already fully inlined via ESPHOME_ALWAYS_INLINE).
Add a new (speed_optimized) message option that emits
__attribute__((optimize("O2"))) on the generated encode() and
calculate_size() methods. Under -Os, GCC does not inline the small
ProtoEncode helpers (write_raw_byte, encode_varint, etc.) into the
generated methods, causing significant overhead on hot paths.
Apply to SensorStateResponse and BluetoothLERawAdvertisementsResponse
which are the highest-frequency encode paths.
Add a new (speed_optimized) message option that emits
__attribute__((optimize("O2"))) on the generated encode() and
calculate_size() methods. Under -Os, GCC does not inline the small
ProtoEncode helpers (write_raw_byte, encode_varint, etc.) into the
generated methods, causing significant overhead on hot paths.
Apply to SensorStateResponse and BluetoothLERawAdvertisementsResponse
which are the highest-frequency encode paths.
CodSpeed benchmarks were building with -O2, while all firmware
targets (ESP8266, ESP32, LibreTiny) use -Os. This mismatch means
the benchmarks cannot detect inlining regressions that affect real
devices — GCC under -O2 inlines functions that -Os outlines due to
its size-conscious cost model.
Switch to -Os with -ffunction-sections/-fdata-sections for proper
dead-code stripping (needed because -Os preserves references that
-O2 optimizes away at compile time).
CodSpeed benchmarks were building with -O2, while all firmware
targets (ESP8266, ESP32, LibreTiny) use -Os. This mismatch means
the benchmarks cannot detect inlining regressions that affect real
devices — GCC under -O2 inlines functions that -Os outlines due to
its size-conscious cost model.
Remove the -Os unflag and -O2 override so benchmarks use the
platform default -Os, matching what actually runs on devices.
J. Nick Koston