andros
fb45f6a582
Mermaid's xychart-beta cannot draw grouped bars or a legend: two bar series overlap on the same axis position, so the paired GPU-vs-cairo comparison was unreadable. Render the charts as images with real grouped bars, value labels and a legend (bench/make-charts.py), and embed them from .github/assets/.
Benchmark harness
Redisplay-throughput benchmarks: the GPU backend vs stock Emacs, on the same binary (GPU on vs off). These produce the tables in the top-level README.md.
Requirements
- An Emacs built
--with-gpu(pointEMACSat it). python3with Pillow and numpy.xvfb-run(only forrun-bench-hires.sh).
Run (GNU/Linux, X11)
# On-screen, ~1616x912 frame on the current display:
EMACS=/path/to/gpu/emacs ./run-bench.sh [RUNS]
# Headless 4K render throughput (GPU renders to an FBO, no present):
EMACS=/path/to/gpu/emacs ./run-bench-hires.sh [RUNS]
Each prints a stock-vs-GPU fps table with the speedup ratio. RUNS defaults to 3; the median is reported.
What it measures
Five workloads, each forcing (redisplay t) per frame (median of N runs, 80-frame warm-up first). GPU side runs vsync off (GL_NO_VSYNC=1) to measure frame cost, not the 60 Hz cap.
| Workload | Stresses |
|---|---|
line-scroll |
one line/frame: few new glyphs (cairo is strong here) |
page-scroll |
one window/frame: many new glyphs |
full-redraw |
redraw-frame: everything repainted |
typing |
one self-insert/frame: minimal dirty rect, floor is one buffer swap |
image-scroll |
scrolling images: cached texture re-composite vs cairo re-blit from CPU |
Buffer: 8000-line font-locked Emacs Lisp; image test uses a synthesized PNG.
Absolute numbers depend on GPU, driver and display server. The meaningful quantity is the ratio between the two modes on the same machine.
Files
gl-bench.el— the workloads. ReadsGL_MODE(gpu/vanilla),GL_BENCH_COLS/GL_BENCH_ROWS,GL_BENCH_OUT. The scripts set these.run-bench.sh— on-screen comparison.run-bench-hires.sh— headless 4K render-throughput comparison.make-charts.py— regenerates the README chart images from the numbers (matplotlib).