bench: live-attach kit — sample/profile a running TUI session (Ink or OpenTUI)

bench/live-attach.sh

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+#!/usr/bin/env bash
+# live-attach.sh — plug into a RUNNING hermes TUI (Ink or OpenTUI) and measure it.
+#
+#   bench/live-attach.sh <pid> [out-dir]          # sample memory+cpu until Ctrl-C
+#   bench/live-attach.sh <pid> --profile [secs]   # also grab a CPU profile window (default 30s)
+#   bench/live-attach.sh <pid> --heap             # grab a heap snapshot (large file!)
+#
+# Find your TUI pid:  pgrep -af 'dist/main.js'        (OpenTUI)
+#                     pgrep -af 'dist/entry.js'       (Ink)
+# Works on any live session — no restart, no flags needed at launch:
+# profiling uses SIGUSR1 (Node opens an inspector port on demand).
+# In-TUI complements (OpenTUI only): /mem (live stats line), /heapdump.
+set -euo pipefail
+PID="${1:?usage: live-attach.sh <pid> [outdir|--profile [secs]|--heap]}"
+shift || true
+OUT="${1:-/tmp/tui-live-$PID}"; MODE="sample"; SECS=30
+[[ "${1:-}" == "--profile" ]] && { MODE=profile; OUT="/tmp/tui-live-$PID"; SECS="${2:-30}"; }
+[[ "${1:-}" == "--heap"    ]] && { MODE=heap;    OUT="/tmp/tui-live-$PID"; }
+mkdir -p "$OUT"
+echo "target pid=$PID cmd=$(tr '\0' ' ' </proc/$PID/cmdline | cut -c1-80)"
+echo "out: $OUT"
+
+sample() {
+  local f="$OUT/samples.jsonl"
+  echo "sampling 1Hz → $f  (Ctrl-C to stop; render: node bench/live-render.mjs $OUT)"
+  local prev_cpu=0 hz; hz=$(getconf CLK_TCK)
+  while kill -0 "$PID" 2>/dev/null; do
+    local rss pss pdirty hwm cpu t
+    rss=$(awk '/^Rss:/{print $2}' /proc/$PID/smaps_rollup 2>/dev/null || echo 0)
+    pss=$(awk '/^Pss:/{print $2}' /proc/$PID/smaps_rollup 2>/dev/null || echo 0)
+    pdirty=$(awk '/^Private_Dirty:/{print $2}' /proc/$PID/smaps_rollup 2>/dev/null || echo 0)
+    hwm=$(awk '/^VmHWM:/{print $2}' /proc/$PID/status 2>/dev/null || echo 0)
+    cpu=$(awk '{print $14+$15}' /proc/$PID/stat 2>/dev/null || echo 0)
+    t=$(date +%s.%N)
+    printf '{"t":%s,"rss_kb":%s,"pss_kb":%s,"private_dirty_kb":%s,"vmhwm_kb":%s,"cpu_ticks":%s,"cpu_hz":%s}\n' \
+      "$t" "$rss" "$pss" "$pdirty" "$hwm" "$cpu" "$hz" >> "$f"
+    sleep 1
+  done
+  echo "process exited; $(wc -l <"$f") samples in $f"
+}
+
+cdp() { # open inspector on demand, find the ws url
+  kill -USR1 "$PID"; sleep 0.7
+  local port; port=$(ss -tlnp 2>/dev/null | grep "pid=$PID" | grep -oE ':(92[0-9]{2})' | head -1 | tr -d ':')
+  [[ -z "$port" ]] && port=9229
+  curl -s "http://127.0.0.1:$port/json" | grep -oE 'ws://[^"]+' | head -1
+}
+
+case "$MODE" in
+  sample) sample ;;
+  profile)
+    WS=$(cdp); echo "CDP: $WS — profiling ${SECS}s (interact with the TUI now!)"
+    node "$(dirname "$0")/live-cdp.mjs" "$WS" profile "$SECS" "$OUT/live.cpuprofile"
+    echo "→ $OUT/live.cpuprofile  (open in https://speedscope.app or chrome://inspect)" ;;
+  heap)
+    WS=$(cdp); echo "CDP: $WS — heap snapshot (may pause the TUI briefly)"
+    node "$(dirname "$0")/live-cdp.mjs" "$WS" heap 0 "$OUT/live.heapsnapshot"
+    echo "→ $OUT/live.heapsnapshot (Chrome DevTools → Memory → Load)" ;;
+esac

bench/live-cdp.mjs

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+#!/usr/bin/env node
+// live-cdp.mjs — minimal CDP client for live-attach.sh (no deps; Node ws via raw socket
+// is overkill — use the built-in WebSocket of Node >=22).
+// usage: node live-cdp.mjs <ws-url> profile <secs> <out> | heap 0 <out>
+const [, , url, mode, secsArg, out] = process.argv
+const { writeFileSync, appendFileSync } = await import('node:fs')
+const ws = new WebSocket(url)
+let id = 0
+const pending = new Map()
+const send = (method, params = {}) =>
+  new Promise((res, rej) => {
+    const i = ++id
+    pending.set(i, { res, rej })
+    ws.send(JSON.stringify({ id: i, method, params }))
+  })
+const chunks = []
+ws.onmessage = e => {
+  const m = JSON.parse(e.data)
+  if (m.id && pending.has(m.id)) {
+    const { res, rej } = pending.get(m.id)
+    pending.delete(m.id)
+    m.error ? rej(new Error(m.error.message)) : res(m.result)
+  } else if (m.method === 'HeapProfiler.addHeapSnapshotChunk') chunks.push(m.params.chunk)
+}
+ws.onopen = async () => {
+  try {
+    if (mode === 'profile') {
+      await send('Profiler.enable')
+      await send('Profiler.start')
+      await new Promise(r => setTimeout(r, Number(secsArg) * 1000))
+      const { profile } = await send('Profiler.stop')
+      writeFileSync(out, JSON.stringify(profile))
+    } else {
+      await send('HeapProfiler.enable')
+      await send('HeapProfiler.takeHeapSnapshot', { reportProgress: false })
+      writeFileSync(out, chunks.join(''))
+    }
+    process.exit(0)
+  } catch (err) {
+    console.error(String(err))
+    process.exit(1)
+  }
+}
+ws.onerror = err => { console.error('ws error', err.message ?? err); process.exit(1) }

bench/live-render.mjs

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+#!/usr/bin/env node
+// live-render.mjs — quick chart from live-attach samples: node bench/live-render.mjs <dir>
+import { readFileSync, writeFileSync } from 'node:fs'
+const dir = process.argv[2] ?? '.'
+const rows = readFileSync(`${dir}/samples.jsonl`, 'utf8').trim().split('\n').map(l => JSON.parse(l))
+const t0 = rows[0].t
+const pts = rows.map(r => ({ t: r.t - t0, rss: r.rss_kb / 1024, hwm: r.vmhwm_kb / 1024 }))
+const W = 900, H = 360, mt = (v, max) => H - 30 - (v / max) * (H - 60)
+const maxY = Math.max(...pts.map(p => p.hwm)) * 1.1
+const path = k => pts.map((p, i) => `${i ? 'L' : 'M'}${30 + (p.t / pts.at(-1).t) * (W - 60)},${mt(p[k], maxY)}`).join('')
+const cpu = rows.map((r, i) => i ? (r.cpu_ticks - rows[i-1].cpu_ticks) / r.cpu_hz / (r.t - rows[i-1].t) : 0)
+writeFileSync(`${dir}/live.svg`, `<svg xmlns="http://www.w3.org/2000/svg" width="${W}" height="${H}" style="background:#0d0d12">
+<text x="30" y="20" fill="#ccc" font-family="monospace">live session: RSS (gold) / VmHWM (grey) MB · avg cpu ${(cpu.reduce((a,b)=>a+b,0)/Math.max(1,cpu.length-1)*100).toFixed(1)}% · ${rows.length}s</text>
+<path d="${path('hwm')}" stroke="#888" fill="none"/><path d="${path('rss')}" stroke="#F5B820" fill="none" stroke-width="2"/>
+<text x="30" y="${H-10}" fill="#888" font-family="monospace">0s</text><text x="${W-80}" y="${H-10}" fill="#888" font-family="monospace">${Math.round(pts.at(-1).t)}s</text>
+<text x="${W-120}" y="${mt(pts.at(-1).rss,maxY)}" fill="#F5B820" font-family="monospace">${pts.at(-1).rss.toFixed(0)}MB</text></svg>`)
+console.log(`${dir}/live.svg`)