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LEDMatrix/test/test_frame_timing.py
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ChuckandClaude Opus 5.5 f79618d4f7 refactor(bench): grade render_bench with the shared frame-timing recorder
render_bench.py (from the parallel perf/render-bench work) had its own
grading module, frame_pacing, with its own definition of a missed frame
and its own refresh estimate. The soak already had both in frame_timing,
so the two could have drifted apart on what "late" means.

The bench now gives the display manager a fresh FrameTimingRecorder,
drains it synchronously at the start and end of the graded run, and prints
frame_soak's report with frame_soak's verdict. Its workload is unchanged:
the synthetic strip, --busy load, the shared speed resolver, the
per-frame scrolling announcement. frame_pacing, its tests and its
src.common exports are removed; measure_refresh_hz moves to frame_timing,
where scroll_speeds.py now finds it.

Two ideas from frame_pacing carry over. The bench seeds the recorder with
the idle refresh it measures, so a loop that free-runs (the 827fps bug
the first bench caught) shows as early frames and one stuck at half rate
as late frames, where an estimate taken from their own intervals finds
both self-consistent. And the soak, which has no idle measurement, now
calls a run NOT LOCKED when its refresh estimate beats the configured cap.
The report also gives the rate held while rendering.

Docs: the bench becomes "Without the service" under "Soaking a rig",
keeping its hdpi numbers and the idle-vs-rendering refresh finding.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-09-24 11:56:44 -04:00

415 lines
15 KiB
Python

"""System-wide frame timing (src/common/frame_timing.py) and its soak report.
The recorder's job is to separate what a viewer sees as a hitch -- a moving
frame one or more refreshes late -- from things that are not jitter: static
screens, the first frame of a scroll, gaps between scrolls, and freezes.
"""
import json
import sys
import time
from pathlib import Path
sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
from src.common import frame_timing # noqa: E402
from src.common.frame_timing import FrameTimingRecorder # noqa: E402
sys.path.insert(0, str(Path(__file__).resolve().parent.parent / "scripts"))
import frame_soak # noqa: E402
PERIOD = 0.010 # a 100Hz panel
def _feed(recorder, intervals, hold=1, scrolling=True, start=100.0,
blit=0.002, wait=0.004):
"""Present one frame, then one more per interval."""
t = start
recorder.record(blit, wait, hold, scrolling, t)
for interval in intervals:
t += interval
recorder.record(blit, wait, hold, scrolling, t)
return t
def _aggregate(recorder):
batch, static = recorder._pending, recorder._static_frames
recorder._pending, recorder._static_frames = [], 0
recorder.aggregate(batch, static)
return recorder.totals
def _recorder(tmp_path):
# A flush interval nothing in these tests reaches, so aggregation is
# driven explicitly and no worker thread starts.
return FrameTimingRecorder(path=str(tmp_path / "stats.json"),
flush_interval=1e9)
def test_steady_frames_are_on_time_and_give_the_refresh(tmp_path):
r = _recorder(tmp_path)
_feed(r, [PERIOD] * 200)
totals = _aggregate(r)
assert totals["scroll_frames"] == 200
assert totals["late_frames"] == 0
assert abs(1.0 / r.refresh_period - 100.0) < 0.5
def test_a_frame_a_refresh_late_is_counted(tmp_path):
r = _recorder(tmp_path)
intervals = [PERIOD] * 200
intervals[50] = 2 * PERIOD # one refresh late
intervals[120] = 4 * PERIOD # three refreshes late
_feed(r, intervals)
totals = _aggregate(r)
assert totals["late_frames"] == 2
assert totals["missed_refreshes"] == 1 + 3
assert totals["late_by"] == {"1": 1, "2": 0, "3-5": 1, "6+": 0}
def test_a_held_frame_is_not_late(tmp_path):
# 50px/s on a 100Hz panel is 1px every 2 refreshes: 20ms is on time.
r = _recorder(tmp_path)
_feed(r, [2 * PERIOD] * 200, hold=2)
totals = _aggregate(r)
assert totals["late_frames"] == 0
assert abs(1.0 / r.refresh_period - 100.0) < 0.5
def test_small_jitter_is_not_late(tmp_path):
r = _recorder(tmp_path)
_feed(r, [PERIOD * (1 + 0.03 * ((i % 5) - 2)) for i in range(300)])
assert _aggregate(r)["late_frames"] == 0
def test_static_frames_and_the_start_of_a_scroll_are_not_timed(tmp_path):
r = _recorder(tmp_path)
t = _feed(r, [1.0, 1.0, 1.0], scrolling=False)
# The first scrolling frame follows a static one 300ms later: that is a
# scroll starting, not a 30-refresh stall.
_feed(r, [PERIOD] * 100, start=t + 0.3)
totals = _aggregate(r)
assert totals["static_frames"] == 4
assert totals["scroll_frames"] == 100
assert totals["late_frames"] == totals["freezes"] == 0
def test_freezes_are_separate_from_late_frames_and_gaps_are_ignored(tmp_path):
r = _recorder(tmp_path)
intervals = [PERIOD] * 200
intervals[80] = 0.400 # a render-thread plugin fetch: freeze
intervals[120] = 1.5 # a longer stall, still inside the scroll: freeze
intervals[150] = 6.0 # past any scroll's inactivity window: ignored
_feed(r, intervals)
totals = _aggregate(r)
assert totals["freezes"] == 2
assert abs(totals["freeze_seconds"] - 1.9) < 1e-9
assert totals["freeze_by"] == {"<0.5s": 1, "0.5-1s": 0, "1-2s": 1, "2s+": 0}
assert totals["late_frames"] == 0
assert totals["scroll_frames"] == 197
def test_a_stall_between_one_and_two_seconds_is_not_lost(tmp_path):
# Two "scrolling" frames can be up to DisplayManager's 2s inactivity
# threshold apart. The first version ignored everything past 1s, so a
# 1.4s render-thread stall vanished from the report.
r = _recorder(tmp_path)
intervals = [PERIOD] * 100
intervals[40] = 1.4
_feed(r, intervals)
assert _aggregate(r)["freezes"] == 1
def test_early_frames_are_counted(tmp_path):
# Hold 2 on a 100Hz panel: frames are due every 20ms. A swap that returns
# after 10ms did not wait out the hold.
r = _recorder(tmp_path)
_feed(r, [2 * PERIOD] * 200, hold=2)
_aggregate(r)
intervals = [2 * PERIOD] * 200
for i in range(0, 200, 20):
intervals[i] = PERIOD
_feed(r, intervals, hold=2, start=1000.0)
totals = _aggregate(r)
assert totals["early_frames"] == 10
assert totals["late_frames"] == 0
def test_refresh_estimate_survives_a_window_full_of_misses(tmp_path):
r = _recorder(tmp_path)
_feed(r, [PERIOD] * 200)
_aggregate(r)
# A bad window where every frame is late must not redefine the refresh.
_feed(r, [2 * PERIOD] * 200, start=1000.0)
totals = _aggregate(r)
assert abs(1.0 / r.refresh_period - 100.0) < 0.5
assert totals["late_frames"] == 200
def test_record_hands_off_and_the_worker_writes_the_file(tmp_path):
path = tmp_path / "stats.json"
r = FrameTimingRecorder(path=str(path), flush_interval=0.5,
info={"cols": 128, "rows": 32})
_feed(r, [PERIOD] * 120) # 1.2s of frames: at least one flush
deadline = time.time() + 5
while not path.exists() and time.time() < deadline:
time.sleep(0.02)
stats = json.loads(path.read_text(encoding="utf-8"))
assert stats["version"] == frame_timing.SCHEMA_VERSION
assert stats["info"]["cols"] == 128
assert stats["totals"]["scroll_frames"] > 0
def test_soak_report_is_the_difference_between_snapshots(tmp_path):
r = _recorder(tmp_path)
_feed(r, [PERIOD] * 200)
_aggregate(r)
before = json.loads(json.dumps(r.snapshot()))
intervals = [PERIOD] * 1000
intervals[500] = 0.0201 # a refresh late; off a bucket boundary
_feed(r, intervals, start=500.0)
_aggregate(r)
after = json.loads(json.dumps(r.snapshot()))
after["updated"] = before["updated"] + 10.0
report = frame_soak.build_report(before, after, preview=True)
assert report["scroll_frames"] == 1000
assert report["late_frames"] == 1
assert report["late_pct"] == 0.1
assert report["timing_ms"]["blit"]["p50"] == 2.25 # 2ms lands in [2, 2.25)
assert report["timing_ms"]["interval_per_hold"]["max"] == 20.25
def test_soak_fails_a_run_that_was_not_locked(tmp_path):
r = _recorder(tmp_path)
_feed(r, [2 * PERIOD] * 200, hold=2)
_aggregate(r)
before = json.loads(json.dumps(r.snapshot()))
_feed(r, [PERIOD] * 1000, hold=2, start=500.0) # never waited out the hold
_aggregate(r)
after = json.loads(json.dumps(r.snapshot()))
after["updated"] = before["updated"] + 10.0
report = frame_soak.build_report(before, after, preview=False)
assert report["late_pct"] == 0.0
assert report["early_pct"] == 100.0
assert not frame_soak.passed(report, 0.1)
def test_soak_percentiles_mark_the_overflow_bucket():
top = frame_timing.BUCKET_COUNT - 1
result = frame_soak.percentiles({0: 98, top: 2}, 0.25)
assert result["p50"] == 0.25
assert str(result["max"]).startswith(">=")
def test_display_manager_records_every_presented_frame():
"""The hook sits in update_display, so every source is covered."""
import os
os.environ["EMULATOR"] = "true"
from src.display_manager import DisplayManager
DisplayManager._instance = None
DisplayManager._initialized = False
dm = DisplayManager({"display": {
"hardware": {"rows": 32, "cols": 64, "chain_length": 1, "parallel": 1},
"runtime": {"gpio_slowdown": 0}}}, suppress_test_pattern=True)
try:
assert dm.frame_timing.info["cols"] == 64
dm.set_scrolling_state(True)
for shade in (10, 20, 30):
dm.draw.rectangle([0, 0, 4, 4], fill=(shade, 0, 0))
dm.update_display()
assert len(dm.frame_timing._pending) == 2 # 3 frames, 2 intervals
finally:
dm.set_scrolling_state(False)
DisplayManager._instance = None
DisplayManager._initialized = False
# --- stall watchdog ----------------------------------------------------------
class _FakeRecorder:
def __init__(self):
self.last_frame = None
self.scrolling = True
self.scrolling_now = lambda: self.scrolling
def test_watchdog_reports_a_stall_once_and_its_end(caplog):
rec = _FakeRecorder()
dog = frame_timing.StallWatchdog(rec, threshold=0.25, log_interval=0.0)
ident = __import__("threading").get_ident()
rec.last_frame = (10.0, True, ident)
with caplog.at_level("WARNING", logger="src.common.frame_timing"):
state = dog.check(10.1, 0.0, None, False) # 100ms: fine
assert state == (None, False)
state = dog.check(10.4, 0.0, *state) # 400ms: stall
assert state == (10.0, True)
state = dog.check(10.9, 0.0, *state) # still stalled: no repeat
rec.last_frame = (11.2, True, ident)
state = dog.check(11.25, 0.0, *state) # a frame arrived
assert state == (None, False)
messages = [r.getMessage() for r in caplog.records]
assert len(messages) == 2
assert messages[0].startswith("Render stall: no frame for 400ms")
assert "test_watchdog_reports_a_stall_once_and_its_end" in messages[0]
assert messages[1] == "Render stall over: no frame for 1200ms"
assert dog.stalls == 1
def test_watchdog_ignores_a_scroll_that_ended(caplog):
rec = _FakeRecorder()
dog = frame_timing.StallWatchdog(rec, threshold=0.25, log_interval=0.0)
rec.last_frame = (10.0, True, 1)
rec.scrolling = False # the scroll handed over
with caplog.at_level("WARNING", logger="src.common.frame_timing"):
assert dog.check(12.0, 0.0, None, False) == (None, False)
assert not caplog.records
def test_watchdog_names_what_the_stalled_thread_is_waiting_on():
import threading
rec = _FakeRecorder()
dog = frame_timing.StallWatchdog(rec)
blocked, release = threading.Event(), threading.Event()
def render_loop_waiting_on_a_lock():
blocked.set()
release.wait(5)
t = threading.Thread(target=render_loop_waiting_on_a_lock, name="render")
t.start()
try:
assert blocked.wait(5)
text = dog.describe(t.ident, 1.5, 1.4)
finally:
release.set()
t.join(5)
assert "no frame for 1500ms" in text
assert "the interpreter itself was blocked" in text
assert "-- render (presents frames):" in text
assert "render_loop_waiting_on_a_lock" in text
def test_watchdog_rate_limits_its_dumps(caplog):
rec = _FakeRecorder()
dog = frame_timing.StallWatchdog(rec, threshold=0.25, log_interval=30.0)
with caplog.at_level("WARNING", logger="src.common.frame_timing"):
for start in (10.0, 20.0): # two stalls 10s apart
rec.last_frame = (start, True, 1)
state = dog.check(start + 0.5, 0.0, None, False)
rec.last_frame = (start + 0.6, True, 1)
dog.check(start + 0.65, 0.0, *state)
dumps = [r for r in caplog.records if r.getMessage().startswith("Render stall:")]
assert len(dumps) == 1
assert dog.stalls == 2
# --- measuring the panel, and runs that never locked -------------------------
# The refresh measurement and the "not locked" cases came from the first
# version of scripts/render_bench.py, which graded runs with its own module.
class FakePanel:
"""A matrix whose swaps block for a fixed period, like real vsync."""
def __init__(self, period, fail=False):
self.period = period
self.fail = fail
self.swaps = 0
def CreateFrameCanvas(self): # noqa: N802 - mirrors rgbmatrix
if self.fail:
raise RuntimeError("no hardware here")
return object()
def SwapOnVSync(self, canvas, framerate_fraction=1): # noqa: N802
self.swaps += 1
time.sleep(self.period)
return canvas
def test_measure_refresh_times_the_swaps_not_the_loop():
# A loop that spun without waiting for each swap would report far more
# than the 200Hz a 5ms swap allows; the lower bound is loose because
# sleep() on a loaded runner overshoots.
measured = frame_timing.measure_refresh_hz(FakePanel(0.005), seconds=0.2)
assert 0 < measured <= 210.0
def test_measure_refresh_discards_the_first_swap():
panel = FakePanel(0.005)
frame_timing.measure_refresh_hz(panel, seconds=0.05)
assert panel.swaps >= 2
def test_measure_refresh_without_hardware_reports_nothing():
assert frame_timing.measure_refresh_hz(FakePanel(0.0, fail=True), seconds=0.1) == 0.0
assert frame_timing.measure_refresh_hz(object(), seconds=0.1) == 0.0
def _seeded(tmp_path, hz=100.0):
return FrameTimingRecorder(path=str(tmp_path / "s.json"),
flush_interval=float("inf"), refresh_hz=hz)
def test_a_seeded_recorder_catches_a_loop_that_never_waited(tmp_path):
# The first bench build free-ran at 827fps once the dirty-tracking skip
# fired mid-scroll. Estimated from its own frames that looks fine; against
# the measured panel rate every frame is early.
r = _seeded(tmp_path)
_feed(r, [0.0012] * 500)
r.drain()
assert r.totals["early_frames"] == 500
assert abs(1.0 / r.refresh_period - 100.0) < 0.5
def test_a_seeded_recorder_catches_a_loop_stuck_at_half_rate(tmp_path):
# Hold 1, but every frame takes two refreshes: self-consistent at 50Hz,
# late on every frame against the panel's 100Hz.
r = _seeded(tmp_path)
_feed(r, [2 * PERIOD] * 500)
r.drain()
assert r.totals["late_frames"] == 500
def test_a_seeded_recorder_still_passes_a_panel_a_little_slower_than_idle(tmp_path):
# 100.4Hz idle, 96.3Hz while rendering: not a single frame is late.
r = _seeded(tmp_path, hz=100.4)
_feed(r, [1 / 96.3] * 500)
r.drain()
assert r.totals["late_frames"] == r.totals["early_frames"] == 0
def test_soak_calls_a_rate_faster_than_the_panel_not_locked(tmp_path):
r = _recorder(tmp_path)
r.info = {"limit_refresh_rate_hz": 100}
before = json.loads(json.dumps(r.snapshot()))
_feed(r, [0.0012] * 500) # unseeded: nothing looks early...
r.drain()
after = json.loads(json.dumps(r.snapshot()))
after["updated"] = before["updated"] + 10.0
report = frame_soak.build_report(before, after, preview=False)
assert report["early_pct"] == 0.0
assert report["measured_refresh_hz"] > 800
assert not frame_soak.locked(report, 0.1) # ...but 833Hz beats a 100Hz cap
assert not frame_soak.passed(report, 0.1)
def test_soak_reports_the_rate_held_while_rendering(tmp_path):
r = _recorder(tmp_path)
before = json.loads(json.dumps(r.snapshot()))
_feed(r, [1 / 96.3] * 500)
r.drain()
after = json.loads(json.dumps(r.snapshot()))
after["updated"] = before["updated"] + 10.0
report = frame_soak.build_report(before, after, preview=False)
assert 95.0 <= report["held_refresh_hz"] <= 97.0
def test_render_bench_strip_lights_a_real_share_of_pixels():
# How long SetImage takes depends on how many subpixels are lit; a mostly
# dark strip would flatter the panel.
import render_bench
strip = render_bench.build_strip(128, 32, "test")
assert strip.width >= 128 * 4
lit = sum(1 for px in strip.getdata() if px != (0, 0, 0))
assert lit / (strip.width * strip.height) > 0.05