DragonFly users List (threaded) for 2010-06
HEAD now has powerd for ACPI based cpu frequency adjustment.
HEAD now has a /usr/sbin/powerd daemon for systems which support
ACPI based cpu frequency adjustment. Your system supports this
if it has the hw.acpi.cpu.px_dom* sysctls:
sysctl hw.acpi | fgrep dom
This is a first attempt from scratch daemon. It takes no arguments
and is very generous. Any 1-second load > 0.25 will set the cpus
to their maximum frequency. When the 10-second load drops down
below 0.12 the cpus will be set to their minimum frequency.
The power savings is usually around 40%. I'm not sure how well it
works for a desktop/X environment as my current workstation has an
old BIOS that doesn't support the feature, but it works very nicely
If the 1-second delay to go to max-frequency isn't fast enough for
a desktop environment we will probably need a kernel facility that
the daemon can block on (so it doesn't have to poll quickly) and
have the kernel wake it up when the instantanious load exceeds a
certain value. That way the daemon would be able to react within
1/10 to 1/15 of a second or so. Maybe the device event stuff being
worked on can be used to support such a facility.