Kernel: 2.6.31.5: CE: hpet increasing min_delta_ns: What do thesemessages mean?

From: Justin Piszcz
Date: Wed Nov 11 2009 - 10:06:44 EST


Hello,

System: Intel DP55KG
CPU: Intel Core i870

I see these messages in my kernel log: (2.6.31.5)

[ 48.886129] CE: hpet increasing min_delta_ns to 15000 nsec
[ 3258.107039] CE: hpet increasing min_delta_ns to 22500 nsec
[53705.451463] CE: hpet increasing min_delta_ns to 33750 nsec

I only see them when ACPI_FREQ and NO_HZ are enabled, to take advantage
of turbo boost.

It is not the result of throttling:

# cat /sys/devices/system/cpu/*/thermal_throttle/count
0
0
0
0
0
0
0
0

Temps are also good, 1 core @ 100% CPU:

Core 0: +41.0°C (high = +84.0°C, crit = +100.0°C) Core 1: +41.0°C (high = +84.0°C, crit = +100.0°C) Core 2: +54.0°C (high = +84.0°C, crit = +100.0°C) Core 3: +54.0°C (high = +84.0°C, crit = +100.0°C) Core 4: +42.0°C (high = +84.0°C, crit = +100.0°C) Core 5: +42.0°C (high = +84.0°C, crit = +100.0°C) Core 6: +42.0°C (high = +84.0°C, crit = +100.0°C) Core 7: +42.0°C (high = +84.0°C, crit = +100.0°C)

I see various discussions on the meaning of these messages but no clear
answer.

Also in reference to loading ACPI_FREQ I mentioned before that when this
module is loaded and there is no CPU activity, there is a high pitch noise
from the CPU/VRM presumably, when ACPI_FREQ is not loaded, this does not
occur, is this expected?

Justin.