1 files changed, 54 insertions, 0 deletions
diff --git a/desktop/modules/perf/vram.sh b/desktop/modules/perf/vram.sh
new file mode 100755
index 0000000..8ba61fb
--- /dev/null
+++ b/desktop/modules/perf/vram.sh
@@ -0,0 +1,54 @@
+#!/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 in bytes from the fdinfo scan: drm-resident-vram0 of every xe fd,
+# counted once per drm-client-id because a client holds several fds. Prints
+# nothing when no xe client is found. With a file argument it reads that
+# instead of scanning, for test_vram.sh.
+#
+# Summed here rather than in JS: a process holding thousands of DRM fds
+# makes the scan a few hundred KB, and parsing that in QML every 2 s 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 (AGENTS.md).
+#
+# Fds of a repeated client id with different values: the first one awk's
+# for-in reaches counts, where Perf.js took the first in scan order. They
+# share one client, so the values agree in practice.
+
+scan() {
+    if [ -n "$1" ]; then cat "$1"
+    else grep -sH -e '^drm-driver' -e '^drm-client-id' -e '^drm-resident-vram0' \
+        /proc/[0-9]*/fdinfo/* 2>/dev/null
+    fi
+}
+
+scan "$1" | awk -F: '
+    NF >= 3 && $2 ~ /^drm-/ {
+        v = $3
+        for (i = 4; i <= NF; i++) v = v ":" $i
+        sub(/^[ \t]+/, "", v)
+        d[$1, $2] = v
+        fd[$1]
+    }
+    END {
+        for (p in fd) {
+            id = d[p, "drm-client-id"]
+            if (d[p, "drm-driver"] != "xe" || id == "" || (id in seen)) continue
+            if (split(d[p, "drm-resident-vram0"], n, " ") < 1 || n[1] !~ /^[0-9]+$/) continue
+            seen[id]
+            u = n[2] == "KiB" ? 1024 : n[2] == "MiB" ? 1048576 : n[2] == "GiB" ? 1073741824 : 1
+            total += n[1] * u
+            any = 1
+        }
+        if (any) printf "%.0f\n", total
+    }'