CLAUDE: perfd - 'measure' now PINS the CPU frequency (min=max) + per-hold overrides

Andrey's observation on the first perfd-held run: CPU boosting to 4.9 GHz,
100 C. Calibration (openssl all-core): the i9-11900K spikes 4.8 GHz @ 85 C,
hits 100 C within seconds and throttles to a wobbling 3.2-3.5 GHz - the
'performance' boost bias is itself a nondeterminism source AND rides Tjmax.
- measure profile: CPU pinned via sysfs scaling_min=max (default 3.2 GHz =
  the measured all-core throttle equilibrium, so the pin holds even in the
  worst phase and runs cooler; PERFD_CPU_LOCK_KHZ) + the existing GPU lock.
  PPD 'performance' hold now only backs the max profile.
- HOLD accepts bounds-checked per-hold overrides (HOLD measure cpu=KHZ
  gpu=MHZ; perfctl passes them through) so lock-value calibration needs no
  daemon reconfiguration/sudo.
- Holds now per-connection with values from the newest holder of the
  winning profile; STATUS extended.
User-mode tested: override parsing/apply, bounds rejection, permission
errors surfaced, auto-release. Root paths activate on reinstall.
Co-authored-by: Claude Opus 4.8 <claude-opus-4-8@anthropic.com>
Co-authored-by: Claude Fable 5 <claude-fable-5@anthropic.com>

perfd/README.md

@@ -24,11 +24,17 @@ install command above when absent (and continues normally).
     perfctl hold max                   # production profile until Ctrl-C
 
 Profiles:
-- `measure` — CPU `performance` + GPU persistence + clocks **locked**
-  (default 2550 MHz, `PERFD_GPU_LOCK_MHZ` in the unit): run-to-run timing
-  reproducibility (±1% instead of ±10% with free-running boost) for per-item
-  performance evaluation.
-- `max` — CPU `performance` + GPU persistence, clocks unlocked: throughput.
+- `measure` — CPU frequency **pinned** (`scaling_min=max`, default 3.2 GHz,
+  `PERFD_CPU_LOCK_KHZ`) + GPU persistence + GPU clocks **locked** (default
+  2550 MHz, `PERFD_GPU_LOCK_MHZ`): run-to-run timing reproducibility (±1%
+  instead of ±10% with free-running boost) for per-item performance
+  evaluation. Pinned, not `performance`: the i9-11900K at free boost hits
+  4.9 GHz → 100 °C → throttle wobble within seconds of an all-core phase
+  (measured 07/17/2026) — boost bias is itself a nondeterminism source.
+  Per-hold overrides: `perfctl hold measure cpu=3400000 gpu=2400 -- <cmd>`
+  (bounds-checked; for calibration without reconfiguration).
+- `max` — CPU `performance` profile (free boost) + GPU persistence, clocks
+  unlocked: throughput.
 
 A hold is tied to the client's connection — process exit or crash releases
 it automatically (refcounted across concurrent holders; `measure` outranks

perfd/elphel-perfd.service

@@ -11,6 +11,7 @@ ExecStart=/usr/bin/python3 /usr/local/lib/elphel-perfd/elphel_perfd.py
 # Config overrides (defaults live in the script):
 #Environment=PERFD_PORT=48890
 #Environment=PERFD_GPU_LOCK_MHZ=2550
+#Environment=PERFD_CPU_LOCK_KHZ=3200000
 #Environment=PERFD_GPU_INDEX=0
 Restart=on-failure
 RestartSec=2

perfd/perfctl

@@ -4,11 +4,14 @@ perfctl - unprivileged client for elphel-perfd (127.0.0.1:48890).
 
     perfctl status                     one-line daemon/clock status
     perfctl ping                       probe (exit 0 = daemon installed)
-    perfctl hold <measure|max>         hold until Ctrl-C
-    perfctl hold <measure|max> -- CMD [ARGS...]
+    perfctl hold <measure|max> [cpu=KHZ] [gpu=MHZ]
+                                       hold until Ctrl-C (overrides optional)
+    perfctl hold <measure|max> [cpu=KHZ] [gpu=MHZ] -- CMD [ARGS...]
                                        hold for the duration of CMD
 The hold is tied to this process's connection: if perfctl dies, the daemon
-releases automatically. By Claude on 07/17/2026.
+releases automatically. cpu=/gpu= override the daemon's 'measure' lock
+defaults (bounds-checked server-side) - for calibration without
+reconfiguration. By Claude on 07/17/2026.
 """
 import os
 import signal
@@ -47,16 +50,20 @@ def main():
     if args[0] == "status":
         print(ask(f, "STATUS"))
         return 0
-    # hold
+    # hold [cpu=KHZ] [gpu=MHZ] [-- CMD...]
     if len(args) < 2 or args[1] not in ("measure", "max"):
         print("perfctl: hold needs a profile: measure | max")
         return 2
-    reply = ask(f, "HOLD " + args[1])
+    overrides = []
+    rest = args[2:]
+    while rest and ("=" in rest[0]) and (rest[0] != "--"):
+        overrides.append(rest.pop(0))
+    reply = ask(f, " ".join(["HOLD", args[1]] + overrides))
     print("perfctl: " + reply)
     if not reply.startswith("OK"):
         return 1
-    if len(args) > 2 and args[2] == "--":
-        rc = subprocess.call(args[3:])
+    if rest and rest[0] == "--":
+        rc = subprocess.call(rest[1:])
         ask(f, "RELEASE")
         return rc
     print("perfctl: holding '%s' until Ctrl-C ..." % args[1])