- Remove 'No __umulsidi3' claim from top comment — the rare path
does use it via /1000. Reworded to 'pure 32-bit ops on the common
path'.
- Extract MILLIS_RARE_PATH_THRESHOLD_US and US_PER_MS constants to
replace magic numbers 10000 and 1000.
Arduino's delay() uses esp_suspend() with a one-shot os_timer for
efficient single-suspension waiting. Our replacement polls millis()
with optimistic_yield(), which also enters esp_schedule/esp_suspend
via yield() but resumes repeatedly. Functionally correct for ESPHome
(delay is cold path, SDK tasks run via yield), just less power-
efficient for long delays.
Split the μs→ms conversion into two paths to keep the interrupt-
disabled critical section bounded:
- Common path (delta < 10 ms): while loop runs at most 10 iterations
(~100 ns). This covers the normal hot-path case where millis() is
called thousands of times per second.
- Rare path (delta >= 10 ms): constant-time multiply-by-reciprocal
via /1000 (compiled to __umulsidi3, ~2.5 μs). Only fires after a
long block (WiFi scan, boot, component stall), where the extra
latency is negligible relative to the block that caused it.
Addresses the concern that a multi-second WiFi scan block could cause
the unbounded while loop to hold interrupts for tens of microseconds.
Merge the separate millis_accumulator() function directly into millis()
to eliminate the extra function call overhead and prologue/epilogue.
Pack the three statics into a struct so the compiler loads one base
address instead of three literal pool entries.
Saves ~12 bytes of IRAM (87+6 → 81 bytes).
Arduino's micros64() reads the same overflow tracking statics that
init() sets up. Wrapping init() as a no-op would cause micros64()
to silently return wrong values after 71 minutes. The overflow timer
cost is negligible (~3 μs per 60 seconds).
Arduino's delay(0) calls yield() once — used as a yield point by some
code. Our millis-based loop would skip yielding entirely since
0 < 0 is false. Add explicit delay(0) → yield() handling.
Arduino's ::delay() is implemented in core_esp8266_wiring.cpp alongside
millis(). Because __delay calls millis() within the same compilation
unit, --wrap=millis can't intercept that intra-object reference, which
prevents the linker from garbage-collecting the original millis body
(~80 bytes of IRAM).
Replace esphome::delay() with a simple yield loop that uses our fast
millis() accumulator. This has the same behavior as Arduino's delay:
feeds the watchdog and processes SDK tasks via yield(), keeping WiFi
alive. With __delay unreferenced, the linker can now GC both __delay
and the original millis function.
Arduino ESP8266's millis() uses 4x 64-bit multiplies with magic
constants to convert system_get_time() to ms while tracking overflow.
On the LX106 (no hardware multiply-high instruction), each 64-bit
multiply goes through the __umulsidi3 software helper — costing
~3.3 us per call.
Replace with a simple accumulator that tracks a running millis counter
from system_get_time() deltas using pure 32-bit integer ops (subtract,
add, compare, subtract). No 64-bit math, no __umulsidi3.
Use -Wl,--wrap=millis to intercept all ::millis() calls site-wide so
Arduino libraries and ISR handlers (Wiegand, ZyAura) also get the fast
version. Brief interrupt disable (~125 ns) protects the static state.
Overflow safety: unsigned 32-bit delta arithmetic handles the 71-minute
system_get_time() wrap correctly for one wrap. ESPHome calls millis()
thousands of times per second, so missing a full wrap is not a realistic
concern. At boot, both the accumulator and system_get_time() start at 0,
so no special initialization is needed.
Benchmarked on real ESP8266 hardware:
Before: 3348 ns/call (Arduino 4x 64-bit multiply)
After: ~800-900 ns/call (accumulator, estimated)
- get_app_state(): say 'STATUS_LED_* only', not 'STATUS_LED_* and lifecycle'
since lifecycle bits are no longer maintained in app_state_.
- STATUS_LED_SETTLE_S: remove incorrect mention of feed_wdt re-dispatch;
status_led_light is driven by the main loop, not feed_wdt.
- snapshot_led service: say 'status_led_light output' not 'pin state'
since the fixture uses a template output, not GPIO.
Extract the 0.3s magic sleep into a named constant explaining why that
duration is chosen (feed_wdt re-dispatches every ~3 ms; 300 ms gives
~100 opportunities). Fix the idle-write check to snapshot AFTER the
clear instead of before it, so writes still in-flight from the error
phase don't inflate the delta.
Verifies that after clearing all status flags, re-setting a flag makes
status_led_light resume writing to its output. Guards against a future
idle optimization (like #15642) where status_led disables its own
loop() when idle: if the re-enable path were broken, the second set
would not produce writes.
Also checks that writes STOP after all flags are cleared (counter
should not keep growing), proving status_led_light correctly stops
blinking in steady state.
Drop the trailing underscore from any_component_has_status_flag now
that the method is public. Trailing underscores in the codebase are
reserved for protected/private members per clang-tidy naming rules,
which caused a CI failure on the previously-named public helper.
Add integration tests covering:
- Single-component status_set/clear for warning and error
- Multi-component OR semantics (both clear orders)
- Warning and error independence
- End-to-end proof that status_led_light::loop() reads App.app_state_
and writes its output when the bits are set (via a fake template
output whose write_action bumps a counter exposed as a sensor)
Application::loop() used to, on every iteration of the inner component
loop, OR each component's state into a local accumulator and then OR
that into this->app_state_, finally overwriting this->app_state_ with
the accumulator after the loop. That was ~5 instructions per component
per loop iteration on the hot path, paying to rebuild state that's
already kept current elsewhere.
STATUS_LED_WARNING / STATUS_LED_ERROR are the only app_state_ bits
anything reads. Component::set_status_flag_() already writes them to
App.app_state_ directly the moment they're set, so any reader (status_led
components, feed_wdt's LED re-dispatch) already sees them without the
per-iter OR. The per-iter OR only ever re-set bits that were already
there — pure dead code on the hot path.
The clear path is handled by moving the work into
status_clear_warning/error_slow_path_(): on a real set->clear transition
the helpers walk App.components_ once to check if any other component
still has the flag, and clear App.app_state_ if not. Clears are rare
relative to loop iterations (a logged transition event), so O(N) per
clear is far cheaper than O(N) per loop.
Setup subtlety: Application::setup()'s slow-setup busy-wait forces
STATUS_LED_WARNING on to blink the LED while a slow component initializes.
A component clear during setup would prematurely wipe that forced bit,
so status_clear_warning_slow_path_() gates its walk-and-clear behind
APP_STATE_SETUP_COMPLETE (a free bit on app_state_ — zero RAM cost).
Application::setup() reconciles the warning state once at the end and
sets the flag. STATUS_LED_ERROR is never forced so its clear path
always walks.
Also fixes a pre-existing bug: the old per-iter accumulation only iterated
looping_components_, so non-looping components' status bits would get
clobbered by the end-of-loop 'app_state_ = new_app_state' overwrite.
The walk-on-clear approach iterates components_ (all of them), so
non-looping components are respected.
Separate Application::feed_wdt() into two entry points so the hot path
callers stop paying for the time==0 check they never trigger:
- feed_wdt_with_time(time): inline, hot path. Rate-limit check in 3
Xtensa instructions (load + sub + branch). [[unlikely]] tells the
compiler the slow branch is rare so the common path stays
fall-through.
- feed_wdt(): cold, out of line. Fetches millis() and forwards through
the same rate limit. Used by setup loops, upload helpers, yield(),
and any other non-hot caller.
feed_wdt_slow_() is now pure worker code — 11 bytes. It just calls
arch_feed_wdt(), updates last_wdt_feed_, and runs the status LED
re-dispatch. Both entries have already confirmed the rate limit was
exceeded before calling.
Hot call sites updated:
- Application::loop() per-component feed
- Scheduler::execute_item_() after each scheduled item runs
- Application::teardown_components() inner loop (already has 'now')
Cleaner than the early-return form — the action (calling feed_wdt_slow_)
reads as the body of the conditional instead of falling through past a
guard clause. Logically identical and compiles to the same code.
The main loop used to feed the watchdog unconditionally right after
Scheduler::call() returned, regardless of whether the scheduler had any
actual work to do. On an idle device this meant every outer loop
iteration paid the inline rate-limit check (load + sub + branch) for no
benefit.
Move the feed into Scheduler::execute_item_() so it fires only after a
scheduled callback actually runs, and covers both the main heap path
and the defer queue path (both go through execute_item_). This also
bounds the max feed gap during a burst of back-to-back scheduled items
by max(item_runtime) instead of sum(item_runtime).
The top-of-loop feed in Application::before_loop_tasks_() is now
unnecessary — when Scheduler::call does no work, the only elapsed time
is the sleep wake plus a few instructions, and when it does have work,
it fed the wdt as it went.
Split Application::feed_wdt() into an ALWAYS_INLINE wrapper that checks
the 3ms rate limit against last_wdt_feed_ and a feed_wdt_slow_() callee
that performs the actual arch_feed_wdt() + status LED re-dispatch.
Callers on the hot path (loop_task before/after each component) that
already have a millis() timestamp in hand now pay only a load + sub +
branch on the no-op path instead of a full call8 / entry / retw.
Moves the rate-limit state from a function-local static to a class
member (last_wdt_feed_) so the inline can access it.
PR #15639 removed Application::register_socket / monitored_sockets_
on the fast-select path before the ota-disable-loop-when-idle merge.
The merge re-introduced the function definitions without the matching
declarations. Drop them.
Following the zephyr_mcumgr precedent, keep the single-instance pointer
as a file-scope static inside ota_esphome.cpp instead of plumbing an
ota_wake_component_ slot and setter through Application. The extern "C"
wake trampoline also lives in the same TU now, so nothing in core/
touches OTA-specific state.
Guard the C and C++ call sites on USE_OTA_PLATFORM_ESPHOME (added as a
-D flag from components/esphome/ota/__init__.py) instead of the broader
ESPHOME_USE_OTA that base ota/ used to emit — the trampoline symbol only
exists when the esphome OTA platform is actually compiled in.
Also drop the dead host yield_with_select_ wake hook (host has no OTA
platform today).
J. Nick Koston