.TH bcm_cpuoff 9

.SH NAME
bcm_cpuoff.ko - power on/off cpu cores to save power

.SH SYNOPSIS
insmod bcm_cpuoff [option=value [option=value] ...]

.SH DESCRIPTION
Simple power-saving module to power-down idle processors, and power-up
offline processors when the system load crosses a user-specified threshold.

.SH OPTIONS
Options may be provided using name=value syntax with insmod command
or modified at run-time by writing the value files of the same in
/sys/modules/bcm_cpuidle/parameters

.IP allow_bits 12
Bitmask for CPUs eligible for power-down.
.br
Default is all CPUs (15 [bottom 4-bits] on 4908)
.IP busy
How busy (ms) before power-up.
.br
Default is 50ms out of default 100ms interval
.IP busy_run
Consecutive busy intervals needed before power-up.
.br
Default is 1
.IP debug
Debug verbosity.
.br
Default is 0 (off)
.IP enable
Enable/disable operation.
.br
Default is 1 (on)
.IP epsilon
How close to full slice (ms).
.br
Default is 5ms
.IP idle_run
Consecutive idle intervals needed before power-down.
.br
Default is 100
.IP period
Delay between system load checks (ms).
.br
Default is 100ms

.SH ALGORITHM
Start high-priority kernel thread that:
.PP
.nf
every interval [100ms]
	for each online cpu
		compute recent idleness from kcpustats
		if cpu-0 idleness is less than busy [50%] threshold
			power-up first allowed cpu that is offline
		else if cpu-n was mostly idle [95%]
			if many [100] consecutive intervals at mostly idle
				power-down cpu if allowed
.PP
Values [in square brackets] above represent the default values which
are configurable as module parameters or at runtime through sysfs.

.SH NOTES
Will not power-up processors which have been powered-down by the thermal
management module which can also power-down processors when temperature
thresholds are exceeded.