feat(perf): show GPU render and compute loadHEADmaster

xe exposes no busy percentage, but its DRM fdinfo carries per-engine
cycle counters. vram.sh becomes gpu.sh: the same scan also sums
drm-cycles-rcs/ccs per client and prints them with the GPU's cycle
counter, and Perf.js turns two scans into a percentage per engine.

The GPU card's headline is now the busier engine, with render (games)
and compute (local LLMs) as bars, then VRAM, temperature and fan.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/desktop/modules/perf/Perf.js b/desktop/modules/perf/Perf.js
index eb0dbd7..b94e5b6 100644
--- a/desktop/modules/perf/Perf.js
+++ b/desktop/modules/perf/Perf.js
@@ -44,6 +44,24 @@ function load(prev, cur) {
     return Math.max(0, Math.min(100, 100 * (1 - (cur.idle - prev.idle) / dt)));
 }
 
+// gpu.sh's line as numbers: [vram, rcs busy, rcs clock, ccs busy, ccs clock],
+// null when it printed nothing.
+function gpuSample(text) {
+    const n = text.trim().split(/\s+/).map(Number);
+    return n.length === 5 && n.every(Number.isFinite) ? n : null;
+}
+
+// {render, compute} percent busy between two gpuSample()s, each null when
+// its clock did not move. A client exiting mid-sample takes its cycles with
+// it, so a dip below zero is clamped.
+function gpuLoad(prev, cur) {
+    const pct = (b, c) => {
+        if (!prev || !cur || cur[c] <= prev[c]) return null;
+        return Math.max(0, Math.min(100, 100 * (cur[b] - prev[b]) / (cur[c] - prev[c])));
+    };
+    return { render: pct(1, 2), compute: pct(3, 4) };
+}
+
 // {total, used} in bytes; used is MemTotal - MemAvailable.
 function meminfo(text) {
     const kb = key => {