Zeb Hering 1be394a0ac Calibrate the CPU ramp per host and fix the deadband leak ...

Two problems found by A/B against Dell's own profile on an R720xd, 8
minute windows at matched CPU temperature:

The CPU ramp started at a fixed 45c, calibrated on a chassis idling at
48c. On one idling at 58c that sat 40% up the ramp doing nothing useful
and ran 6878 RPM against stock's 6240. The ramp is now derived from the
CPU sensor's own upper-non-critical threshold, and the fan floor is
per-host since PWM->RPM is chassis specific.

The 5 minute re-assert re-pushed the current request rather than the
held value, so the deadband leaked a few percent every interval and the
setpoint drifted 32 -> 36 -> 31. next_fan_speed now separates "has it
moved enough to adopt" from "is it time to re-push".

Also documents that running above stock is correct on hosts whose drives
need it: removing the drives' vote on iz-pve0 hit stock RPM exactly and
took two rear-bay SSDs from 54c to 61c in minutes.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

2026-08-28 21:12:54 -07:00

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