perf: sum VRAM in a shell script instead of in QML

A process holding thousands of DRM fds makes the fdinfo scan a few
hundred KB. Parsing that in QML every 2s drove Qt's unmanaged-heap
counter to underflow, after which the V4 engine ran a GC on every
allocation and the shell sat at 100% CPU.

vram.sh does the scan and the per-client-id sum in awk and prints one
number, or nothing when no xe client is found, which the panel draws as
a dash. Perf.js loses vram() and its test; test_vram.sh carries the same
cases against the script, which takes a file argument instead of
scanning so the test can feed it.

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

1 files changed, 40 insertions, 0 deletions

diff --git a/desktop/modules/perf/test_vram.sh b/desktop/modules/perf/test_vram.sh
new file mode 100755
index 0000000..7ef4ade
--- /dev/null
+++ b/desktop/modules/perf/test_vram.sh
@@ -0,0 +1,40 @@
+#!/bin/sh
+#
+# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+
+# vram.sh: summed once per xe client id, units honoured, other drivers
+# ignored; nothing at all when no xe client is found.
+set -e
+dir=$(dirname "$0")
+tmp=$(mktemp)
+trap 'rm -f "$tmp"' EXIT
+
+printf '%s\n' \
+    "/proc/1/fdinfo/7:drm-driver:	xe" \
+    "/proc/1/fdinfo/7:drm-client-id:	38" \
+    "/proc/1/fdinfo/7:drm-resident-vram0:	1024 KiB" \
+    "/proc/1/fdinfo/10:drm-driver:	xe" \
+    "/proc/1/fdinfo/10:drm-client-id:	38" \
+    "/proc/1/fdinfo/10:drm-resident-vram0:	1024 KiB" \
+    "/proc/2/fdinfo/5:drm-driver:	xe" \
+    "/proc/2/fdinfo/5:drm-client-id:	40" \
+    "/proc/2/fdinfo/5:drm-resident-vram0:	2 MiB" \
+    "/proc/3/fdinfo/4:drm-driver:	amdgpu" \
+    "/proc/3/fdinfo/4:drm-client-id:	1" \
+    "/proc/3/fdinfo/4:drm-resident-vram0:	9 GiB" > "$tmp"
+got=$(sh "$dir/vram.sh" "$tmp")
+[ "$got" = $((1024 * 1024 + 2 * 1024 * 1024)) ] || { echo "vram: got '$got'"; exit 1; }
+
+: > "$tmp"
+got=$(sh "$dir/vram.sh" "$tmp")
+[ -z "$got" ] || { echo "empty: got '$got'"; exit 1; }
+echo ok