* perf(timing): say which render-thread work a late frame followed
The soak already says how often a moving frame reached the panel late, but
not what the render thread was doing just before it. Vegas does two kinds of
work there between frames -- building its strip (compose, extend) and, with
live elements, patching changed pixels into it -- and deciding whether either
is affordable needs their own numbers.
- FrameTimingRecorder.note_op(kind, nbytes) tags the next presented frame.
Totals gain op_frames, late_op_frames, op_freezes and op_bytes per kind;
aggregate() still takes frames without ops. The file schema is unchanged.
- Vegas tags compose and every strip extension (with the bytes it copied).
- frame_soak prints an "after work" table: frames, late %, freezes and MB
moved per kind, only when something tagged its work.
- render_bench gains --strip-screens (Vegas-sized strips), --patch-bytes /
--patch-every / --patch-where (in-place column writes, as a live element
update does) and --extend-every-screens / --extend-width (append + trim on
a fixed cadence that holds the strip's width).
No runtime behaviour changes: this is the measurement gate for live Vegas
elements.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* docs(changelog): note the frame-op attribution and bench modes
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* perf(scroll): build the strip's PIL image only when something reads it
Every Vegas strip extension rebuilt ScrollHelper.cached_image from
cached_array in full, twice (append, then trim), on the render thread:
Image.fromarray is 1.7ms for an 8,000px strip and 3.8ms for 20,000px on a
Pi 4 (measured on ledpi), about two thirds of an extension's render-thread
cost. Nothing on the frame path reads the image's pixels; every frame is cut
from the array.
cached_image is now a property. append_content and drop_scrolled_prefix
defer it; the first read builds it from the array it started with and keeps
it only if the strip has not changed meanwhile, so a sync push racing an
extension cannot leave a stale image cached. Assigning cached_image stores
exactly what was assigned, as before. has_strip() says whether there is a
strip without building its image; the helper's frame path, Vegas and the
adapter's scroll-cache invalidation use it. The strip is also no longer held
in memory twice.
In Vegas the image is now built only by a multi-display sync push.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
