mirror of
https://github.com/ChuckBuilds/LEDMatrix.git
synced 2026-10-04 22:35:08 +00:00
e6e0a16140683585997c649bc4a4b1bc2c242c82
1
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
|
|
d12323e7f1 |
perf(scroll): pace frames to the panel — 44→100 fps, stalls 14% → 0.02% (#523)
* perf(scroll): pace frames to the panel, not to a fixed sleep Scrolling ran at 44-46 fps on a 2x128x64 chain and 14-17% of frames took 41-53ms, which reads as judder. Four independent causes, each measured on the hardware; details and the diagnostic recipe are in docs/SCROLL_PERFORMANCE.md. The high-FPS loop slept a flat 8ms after every render. display() has already blocked on the panel's vsync by then, so that sleep was added to a wait that had happened: ~4ms of render plus 8ms put each iteration at ~12ms against a 10ms refresh grid, so every swap missed a refresh and the loop settled at 50fps while asking for 125 -- with no headroom, so a further 14% of frames slipped again. It now sleeps only the remainder, with a 1ms floor so plugin threads still get the GIL. ScrollHelper stepped position on a wall clock at 1/scroll_delay steps per second. Plugins set scroll_delay to the frame period, so that comparison sat exactly on its own threshold: a frame arriving a hair early moved zero pixels and rendered an identical frame, dirty-tracking skipped the swap, it returned in ~2ms, and the beat repeated. No scroll_delay value tunes that out -- a shorter delay trades stalled frames for periodic double-steps. Both modes now accumulate elapsed time at the same configured speed, so position stays proportional to real time. Sub-pixel blending goes back to off by default. It renders a half-step by mixing two adjacent columns, which on a coarse panel showing pixel-font text alternates crisp and smeared frames and reads as shimmer -- visibly worse than integer stepping on the hardware. Vegas mode still opts in. disk_cache uses orjson when importable, falling back to the stdlib. Encoding a ~1MB record drops from 14.8ms to 5.4ms end-to-end, and that work holds the GIL while a marquee is on screen. display_manager also checksummed the whole framebuffer twice per frame (dirty tracking, then the preview snapshot); the snapshot now takes the checksum the caller already computed. New src/common/scroll_config.py resolves scroll settings in one place. Five ticker plugins each hand-rolled this and disagreed: odds-ticker ranked the deprecated scroll_pixels_per_second above the documented scroll_speed/delay pair, and because that key carries a schema default the documented settings were dead for every user (ChuckBuilds/ledmatrix-plugins#408), while ledmatrix-leaderboard read the same key only as a fallback. The resolver also warns when a speed will not advance a whole number of pixels per refresh, which is the property that actually determines whether a scroll looks smooth. scripts/build_rgbmatrix_nogil.sh rebuilds the rgbmatrix binding so it releases the GIL. Upstream declares SwapOnVSync without nogil, unlike SetPixel/Clear/Fill beside it, so the render thread held the GIL for the whole vsync wait and starved background threads into long uninterruptible bursts. The script patches, builds and self-verifies into a scratch tree; --install backs up the original and rolls back if the service does not come back healthy. Measured after: 100 fps locked, no stalls observed, render thread down from 51% to 19% of one core. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * fix(display): keep the panel swap locked to vsync while scrolling Dirty tracking skipped SwapOnVSync for byte-identical frames. That is the right call for static content, but SwapOnVSync is also what paces the render loop, so skipping it skips the wait for the panel: a duplicate frame returns in ~8ms instead of ~10ms on a 100Hz panel, advances the strip only 0.8px instead of 1.0px, and so makes the next frame more likely to repeat as well. The effect sustains itself once it starts. Measured over 20 minutes on a 2x128x64 chain, both scrollers configured identically at 100 px/s: leaderboard 10ms x35, 11ms x3 (clean) odds-ticker 10ms x26, 8ms x7, 15ms x5 (~20% duplicates mid-scroll) The duplicates were not end-of-cycle idling -- 38% of fast frames fell within 90s of a scroll completion against 35% of normal frames, a null result. The trigger is per-frame work: odds does more of it, and more variably, so it is first to land a frame that advances less than a whole pixel. Pushing an identical frame costs one canvas copy. Falling out of vsync lock costs smooth motion. Static content is untouched, because is_currently_scrolling() expires on its own inactivity threshold -- covered by test_stale_scrolling_state_stops_forcing_pushes so a plugin that stops scrolling without saying so cannot pin the panel into always-push. Also de-flakes test_snapshot_still_written_on_skip, which asserted a strict mtime increase between two writes that can land in the same filesystem tick; it failed about two runs in three on Windows regardless of the code under test. The file is now backdated before the check. 156 tests pass on the Pi. Not yet confirmed by eye on the panel. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * fix(scroll): report the frame-time tail, and stop the row-major blit Two problems, both found by looking at the panel rather than the metric. The frame-stats line reported ONE instantaneous frame every 5 seconds -- about 1 frame in 500 -- printed beside a 100-frame average. Both hide exactly the fault they are used to chase: a 2ms duplicate and a 21ms double-wait average to precisely 10ms, so a ticker stalling on half its frames still reports a healthy "Avg FPS: 100.0". That reading cost several rounds of chasing the wrong layer. The line now aggregates every frame since the last log and reports median, p95, max, min, and explicit stall and skip rates (past 1.5x the median missed a refresh; under half never reached the panel, because dirty tracking skipped the swap so the frame never waited on vsync). On the hardware this now reads: leaderboard 100.0 fps over 501 frames | median 10.00ms p95 10.05ms max 10.34ms | stalls 0 (0.0%) skips 0 (0.0%) The binding rebuild's blit patch becomes opt-in (RGB_PATCH_BLIT=1, default off). Reordering that loop to row-major changes what a torn frame looks like: column-major tearing shows as a vertical seam, row-major as a horizontal split between the panel's upper and lower halves. On a 1/32 scan panel that reads as a one-pixel fold across the middle of every panel, which is what was reported on hardware and what went away when the blit was reverted. All of the measured gain comes from the SwapOnVSync change, so the risky half is simply not worth taking; the header says so. Also fixes --install resolving its paths against $HOME, which is /root under sudo, so it looked in /root/rgbmatrix-nogil-build and died with "no built module found" on a machine where the build had just succeeded. It now resolves SUDO_USER's home. Both build paths are verified on the Pi: default yields one GIL-release site, RGB_PATCH_BLIT=1 yields two. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * feat(scroll): let users pick a crisp speed for their own panel Whole-pixel motion was previously only available at multiples of the refresh rate -- 100, 200, 300 px/s on a 100Hz panel. 100 px/s crosses a 256px panel in 2.6s, which is brisk for reading, and everything slower had to blend (blur) or repeat frames unevenly (judder). There was no way to ask for 50 px/s and get clean motion. SwapOnVSync takes a framerate_fraction the display manager never passed. It holds each frame for N panel refreshes; the panel keeps refreshing at its full rate throughout, so holding costs nothing in flicker and only changes how often a NEW image is presented. That turns 50 px/s into one whole pixel every second refresh instead of half a pixel every refresh. The crisp speeds are therefore refresh_hz / hold * pixels_per_frame, and that ladder depends on the panel: a Pi Zero on a long chain has a different set of good speeds from a Pi 4 on a short one. crisp_ladder() enumerates them and solve_crisp() picks the best match for a requested speed. solve_crisp weights motion quality rather than picking the numerically nearest entry, which matters more than it sounds. Asked for 30 px/s, nearest-by-value answers 28.6 -- 2px jumps at 14fps -- over 33.3, which is single-pixel motion at 33fps and obviously better on the panel. The target is also clamped into the ladder's range first, because relative error saturates near 1.0 for a target far outside it and the quality penalty would otherwise answer "10000 px/s" with the slowest entry. configure() snaps to the ladder and applies the hold when given a display manager. Without one the hold silently cannot happen and motion falls back to fractional pixels, so it warns rather than failing quietly. set_frame_hold() resets to 1 when scrolling stops, so one plugin's pacing cannot leak into whatever is on screen next. scripts/scroll_speeds.py is the user-facing part: it prints the ladder for the configured rate, measures what the panel ACTUALLY manages (--measure, for hardware that cannot reach its configured limit), highlights the nearest option to a wanted speed, and demos one live. It never starts or stops the display service itself -- doing that inside a script stranded the panel twice today. Speeds below ~20 px/s remain stepped regardless. That is the pixel pitch, not a software limit. Also fixes the dirty-tracking test spy, which stubbed SwapOnVSync with a single-argument function and would have masked the new call as a failed push, and rewrites a configure() test that had started passing for the wrong reason: it asserted a judder warning, which snapping now prevents, and was matching the unrelated "hold could not be applied" warning instead. 183 tests pass on the Pi. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * fix(scroll): tie the frame hold to the scroll, not the plugin The hold applied in configure() never reached the panel. Plugins share one display manager, and set_scrolling_state(False) -- fired whenever ANY other plugin finishes its scroll -- reset the hold to 1. A hold set once at plugin construction was therefore always gone by the time that plugin rendered. The symptom was a log line that lied. ledmatrix-stocks reported Scroll configured: 50.0 px/s (1px every 2 refreshes = 50.0 fps, smooth) while the panel measured 100.0 fps, median 10.00ms. Config, resolution and snapping were all correct; only the pacing silently was not applied. set_scrolling_state(is_scrolling, frame_hold=1) now carries it, so the hold lives exactly as long as the scroll that asked for it. configure() reports the value as ScrollSettings.frame_hold instead of applying it -- applying it behind the caller's back could never have been right on a shared display manager. Existing callers are unaffected; the default keeps one frame per refresh. Verified on hardware: stocks at 50 px/s now measures 50.0 fps over 251 frames | median 20.00ms p95 20.09ms | stalls 0 skips 0 20.00ms being exactly two refreshes, with the panel still refreshing at 100Hz underneath so flicker is unchanged. test_another_plugin_stopping_does_not_strand_a_hold pins the interaction that broke this. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * fix(scroll,cache): resolve CodeRabbit review on #523 Eight findings, all reproduced before fixing. scroll_config.configure() read the refresh rate *after* resolve() had already used it. resolve() fills in target_fps, pixels_per_frame and the judder warning from that rate, so on a 60Hz panel every one of them described 100Hz -- and with snap_to_crisp=False nothing downstream corrected it, so set_target_fps() paced the helper to 100 FPS. The rate is now settled first, and falls back to the global config rather than straight to the default. refresh_hz_from_config() used `(cfg.get("display") or {}).get(...)`, which raises AttributeError when either level is truthy but not a mapping -- out of a function whose whole contract is a rate or a default. The frame-stats line reported the upper-middle sample as the median and the 96th sorted sample as p95 of 100. Both are also thresholds (stalls at 1.5x the median, skips at 0.5x), so the counts were biased too. The arithmetic is now in frame_stats()/format_frame_stats(), testable without a clock. configure()'s docstring and docs/SCROLL_PERFORMANCE.md still said it applies the frame hold and warns when it cannot. It deliberately does neither since "tie the frame hold to the scroll, not the plugin"; a caller following the old text would omit set_scrolling_state() and slow snapped speeds would still present every refresh. disk_cache had no policy for non-finite floats: orjson writes null, the stdlib writes NaN/Infinity, and orjson then rejects those legacy files so DiskCache.get deleted them as corrupt. One behaviour on both paths now -- write null, keep legacy records readable. allow_nan=False detects the values; the replacement walk runs only when there is one, so the ordinary write path is byte-identical and pays nothing. build_rgbmatrix_nogil.sh picked the build artifact with a glob piped to `head -1`, which sorts cpython-311 ahead of cpython-313, so a stale .so staged in from the source tree was installed as core.so while the GIL check -- which reads the generated core.cpp, not the .so -- still passed. It now requires the current interpreter's exact ABI name and fails closed. Its systemctl calls were also unchecked under `set -uo pipefail`: a failed stop left the old service running, the following start succeeded as a no-op, and the health check reported SUCCESS for a binding that was never loaded. orjson floor raised to 3.11.6 for CVE-2025-67221 (unbounded recursion in dumps); it covers the project's Python 3.10-3.13 range. Adds test/test_cache_nonfinite_floats.py (14) plus regression tests in test_scroll_config.py and test_scroll_helper.py. 9 of the cache tests and 9 of the scroll_config tests fail against the pre-fix code. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_014RRtqXDCnvnY6EQwhT5CV9 * test(harness): keep the visual double's signature tied to production Moves set_scrolling_state's frame_hold into the test double here, where DisplayManager gains it, rather than in #534 where it arrived a PR early. CodeRabbit flagged the #534 version correctly: a double that accepts an argument production does not lets the call pass every harness run and raise TypeError on the panel, which is the one failure a safety harness exists to prevent. The drift has now gone both ways across two branches -- double behind production on this branch, double ahead of it on #534 -- so it is pinned instead of remembered. test_display_double_parity.py compares the two signatures and fails with the direction of the drift named. It reads the files with ast rather than importing them, because display_manager imports rgbmatrix at module scope and this check should hold on a laptop and in CI as well as on a Pi. Plugins begin passing frame_hold in ledmatrix-plugins#462, which is why production and the double both need it before that lands. Full suite: 3889 passed. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_014RRtqXDCnvnY6EQwhT5CV9 --------- Co-authored-by: Claude Opus 5 <noreply@anthropic.com> |