system-monitor: GPU, Network, and Power cards in bTop

Three more same-level grid cards (bTop now 7 cards; Temperature stays under
Memory via natural 3-col flow):
- GPU: gpu_busy_percent + VRAM used/total from /sys/class/drm (instant).
- Network: ↓/↑ throughput (bytes/sec) from /proc/net/dev deltas between /stats
  calls, aggregate + top interfaces.
- Power: CPU package watts via RAPL energy delta + GPU watts (amdgpu hwmon).

Note: RAPL energy_uj is root-only by default (Spectre-era lockdown), so CPU
package power shows "—" unless made readable (a udev rule); GPU watts work.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/servers/api/system-monitor/system-monitor.ts

@@ -137,6 +137,97 @@ async function readTemps() {
   return { cpuC: cpu?.celsius ?? null, cpuLabel: cpu ? `${cpu.name} · ${cpu.label}` : null, sensors };
 }
 
+// GPU (amdgpu/intel): busy% + VRAM, read straight from /sys/class/drm (instant, no sampling).
+async function readGpu() {
+  let cards: string[];
+  try {
+    cards = await readdir('/sys/class/drm');
+  } catch {
+    return null;
+  }
+  for (const c of cards.sort()) {
+    if (!/^card\d+$/.test(c)) continue;
+    const dev = `/sys/class/drm/${c}/device`;
+    const busyRaw = await readFile(`${dev}/gpu_busy_percent`, 'utf8').catch(() => null);
+    if (busyRaw == null) continue;
+    const busyPct = Number.parseInt(busyRaw.trim(), 10);
+    const vramUsed = Number.parseInt((await readFile(`${dev}/mem_info_vram_used`, 'utf8').catch(() => '0')).trim(), 10) || 0;
+    const vramTotal = Number.parseInt((await readFile(`${dev}/mem_info_vram_total`, 'utf8').catch(() => '0')).trim(), 10) || 0;
+    return { busyPct: Number.isFinite(busyPct) ? busyPct : 0, vramUsedBytes: vramUsed, vramTotalBytes: vramTotal };
+  }
+  return null;
+}
+
+// Network throughput — bytes/sec computed from the delta since the previous /stats call (~2s window).
+let lastNet: { total: { rx: number; tx: number }; per: Record<string, { rx: number; tx: number }>; ts: number } | null = null;
+async function readNet() {
+  const now = Date.now();
+  let data: string;
+  try {
+    data = await readFile('/proc/net/dev', 'utf8');
+  } catch {
+    return null;
+  }
+  const per: Record<string, { rx: number; tx: number }> = {};
+  let totRx = 0;
+  let totTx = 0;
+  for (const line of data.split('\n')) {
+    const m = line.match(/^\s*([^:]+):\s*(.+)$/);
+    if (!m) continue;
+    const iface = m[1]!.trim();
+    if (iface === 'lo') continue;
+    const cols = m[2]!.trim().split(/\s+/).map(Number);
+    const rx = cols[0] ?? 0;
+    const tx = cols[8] ?? 0;
+    per[iface] = { rx, tx };
+    totRx += rx;
+    totTx += tx;
+  }
+  const prev = lastNet;
+  lastNet = { total: { rx: totRx, tx: totTx }, per, ts: now };
+  if (!prev || now <= prev.ts) return { rxBytesPerSec: 0, txBytesPerSec: 0, interfaces: [] as { name: string; rxBytesPerSec: number; txBytesPerSec: number }[] };
+  const dt = (now - prev.ts) / 1000;
+  const rate = (cur: number, old: number) => Math.max(0, Math.round((cur - old) / dt));
+  const interfaces = Object.entries(per)
+    .map(([name, v]) => ({ name, rxBytesPerSec: rate(v.rx, prev.per[name]?.rx ?? v.rx), txBytesPerSec: rate(v.tx, prev.per[name]?.tx ?? v.tx) }))
+    .filter((i) => i.rxBytesPerSec > 0 || i.txBytesPerSec > 0)
+    .sort((a, b) => b.rxBytesPerSec + b.txBytesPerSec - (a.rxBytesPerSec + a.txBytesPerSec));
+  return { rxBytesPerSec: rate(totRx, prev.total.rx), txBytesPerSec: rate(totTx, prev.total.tx), interfaces };
+}
+
+// Power draw — CPU package watts from the RAPL energy counter (delta since last call) + GPU watts
+// (amdgpu hwmon, instant).
+let lastRapl: { uj: number; ts: number } | null = null;
+async function readPower() {
+  const now = Date.now();
+  let cpuWatts: number | null = null;
+  const ujRaw = await readFile('/sys/class/powercap/intel-rapl:0/energy_uj', 'utf8').catch(() => null);
+  if (ujRaw != null) {
+    const uj = Number.parseInt(ujRaw.trim(), 10);
+    const prev = lastRapl;
+    lastRapl = { uj, ts: now };
+    if (prev && now > prev.ts && uj >= prev.uj) {
+      cpuWatts = Math.round(((uj - prev.uj) / 1e6 / ((now - prev.ts) / 1000)) * 10) / 10;
+    }
+  }
+  let gpuWatts: number | null = null;
+  try {
+    for (const d of await readdir('/sys/class/hwmon')) {
+      const base = `/sys/class/hwmon/${d}`;
+      if ((await readFile(`${base}/name`, 'utf8').catch(() => '')).trim() !== 'amdgpu') continue;
+      const p = (await readFile(`${base}/power1_average`, 'utf8').catch(() => null)) ?? (await readFile(`${base}/power1_input`, 'utf8').catch(() => null));
+      if (p != null) {
+        const uw = Number.parseInt(p.trim(), 10);
+        if (Number.isFinite(uw)) gpuWatts = Math.round((uw / 1e6) * 10) / 10;
+      }
+      break;
+    }
+  } catch {
+    /* no amdgpu */
+  }
+  return { cpuWatts, gpuWatts };
+}
+
 systemMonitorRouter.get('/stats', async (ctx) => {
   const first = await readCpuSample().catch(() => null);
   await new Promise((r) => setTimeout(r, 120));
@@ -152,11 +243,14 @@ systemMonitorRouter.get('/stats', async (ctx) => {
         })
       : [];
 
-  const [mem, disks, processes, temp] = await Promise.all([
+  const [mem, disks, processes, temp, gpu, net, power] = await Promise.all([
     readMem().catch(() => null),
     readDisks(),
     readProcesses(),
     readTemps().catch(() => null),
+    readGpu().catch(() => null),
+    readNet().catch(() => null),
+    readPower().catch(() => null),
   ]);
 
   const cpus = os.cpus();
@@ -175,6 +269,9 @@ systemMonitorRouter.get('/stats', async (ctx) => {
     disks,
     processes,
     temp,
+    gpu,
+    net,
+    power,
     timestamp: Date.now(),
   });
 });