Package com.digi.android.system.cpu

Class GovernorInteractive

java.lang.Object

com.digi.android.system.cpu.Governor

com.digi.android.system.cpu.GovernorInteractive

public class GovernorInteractive
extends Governor

Represents a governor of type 'interactive'. It is designed for latency-sensitive, interactive workloads. This governor sets the CPU speed depending on usage, similar to 'ondemand' and 'conservative' governors, but with a different set of configurable behaviors.

Field Summary

Fields

Modifier and Type	Field	Description
static long	MAX_ABOVE_HIGH_SPEED_DELAY	Maximum value of above high speed delay time: microseconds.
static long	MAX_BOOSTPULSE_DURATION	Maximum value of boost pulse duration: microseconds.
static long	MAX_MIN_SAMPLE_TIME	Maximum value of minimum sample time: microseconds.
static long	MAX_TIMER_RATE	Maximum value of timer rate: microseconds.
static long	MAX_TIMER_SLACK	Maximum value of timer slack: microseconds.

Fields inherited from class com.digi.android.system.cpu.Governor

governorType, manager, PATH_GOVERNOR_SETTINGS

Method Summary

Modifier and Type	Method	Description
void	disableBoost()	Disables the boost.
void	enableBoost()	Enables the boost.
long	getAboveHiSpeedDelay()	Gets the above high speed delay time in uS (10^-6 seconds).
boolean	getBoost()	Returns whether boost is enabled or disabled.
long	getBoostPulseDuration()	Gets the length of time to hold CPU speed in uS (10^-6 seconds) at high speed frequency on a boost pulse (@see #CPUManager.boostPulse()), before allowing speed to drop according to load as usual.
int	getGoHiSpeedLoad()	Gets the CPU load percentage at which to ramp to the intermediate 'High speed'.
int	getHiSpeedFreq()	Gets the high speed frequency value at which to initially ramp when CPU load hits the high speed load value.
long	getMinSampleTime()	Gets the minimum sample time in uS (10^-6 seconds).
protected java.lang.String	getTag()	Returns the class tag used for logging purposes.
long	getTimerRate()	Gets the sample rate in uS (10^-6 seconds) for reevaluating CPU load when the system is not idle.
long	getTimerSlack()	Gets the maximum additional time in uS (10^-6 seconds) to defer handling the governor sampling timer beyond 'Timer rate' when running at speeds above the minimum.
void	setAboveHiSpeedDelay(long delay)	Sets the above high speed delay time in uS (10^-6 seconds).
void	setBoostPulseDuration(long time)	Sets the length of time in uS (10^-6 seconds) to hold CPU speed at high speed frequency on a write boost pulse (@see #CPUManager.boostPulse()), before allowing speed to drop according to load as usual.
void	setGoHiSpeedLoad(int load)	Sets the CPU load percentage at which to ramp to the intermediate 'High speed'.
void	setHiSpeedFreq(int frequency)	Sets the high speed frequency value at which to initially ramp when CPU load hits the high speed load value.
void	setMinSampleTime(long time)	Sets the minimum sample time in uS (10^-6 seconds).
void	setTimerRate(long rate)	Sets the sample rate in uS (10^-6 seconds) for reevaluating CPU load when the system is not idle.
void	setTimerSlack(long time)	Sets the maximum additional time in uS (10^-6 seconds) to defer handling the governor sampling timer beyond 'Timer rate' when running at speeds above the minimum.

Methods inherited from class com.digi.android.system.cpu.Governor

getGovernorType, getSettingPath, readFile, writeFile

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MAX_MIN_SAMPLE_TIME

public static final long MAX_MIN_SAMPLE_TIME

Maximum value of minimum sample time: microseconds.

See Also:

Constant Field Values

MAX_ABOVE_HIGH_SPEED_DELAY

public static final long MAX_ABOVE_HIGH_SPEED_DELAY

Maximum value of above high speed delay time: microseconds.

See Also:

Constant Field Values

MAX_TIMER_RATE

public static final long MAX_TIMER_RATE

Maximum value of timer rate: microseconds.

See Also:

Constant Field Values

MAX_TIMER_SLACK

public static final long MAX_TIMER_SLACK

Maximum value of timer slack: microseconds.

See Also:

Constant Field Values

MAX_BOOSTPULSE_DURATION

public static final long MAX_BOOSTPULSE_DURATION

Maximum value of boost pulse duration: microseconds.

See Also:

Constant Field Values

Method Detail

getTag

protected java.lang.String getTag()

Description copied from class: Governor

Returns the class tag used for logging purposes.

Specified by:

getTag in class Governor

Returns:

The class tag.

setMinSampleTime

public void setMinSampleTime(long time)
                      throws CPUException

Sets the minimum sample time in uS (10^-6 seconds). This parameter represents the minimum amount of time to spend at the current frequency before ramping down. This is to ensure that the governor has seen enough historic CPU load data to determine the appropriate workload.

Default is 80000 uS.

Parameters:

time - The new minimum sample time in uS (10^-6 seconds)

Throws:

CPUException - If there is an error during the configuration process.

java.lang.IllegalArgumentException - If time < 0 or if time > MAX_MIN_SAMPLE_TIME.

See Also:

MAX_MIN_SAMPLE_TIME, getMinSampleTime()

getMinSampleTime

public long getMinSampleTime()
                      throws CPUException

Gets the minimum sample time in uS (10^-6 seconds). This parameter represents the minimum amount of time to spend at the current frequency before ramping down. This is to ensure that the governor has seen enough historic CPU load data to determine the appropriate workload.

Default is 80000 uS.

Returns:

The minimum sample time in uS (10^-6 seconds), -1 if the value could not be read.

Throws:

CPUException - If there is an error during the configuration process.

See Also:

setMinSampleTime(long)

setHiSpeedFreq

public void setHiSpeedFreq(int frequency)
                    throws CPUException

Sets the high speed frequency value at which to initially ramp when CPU load hits the high speed load value.

Default is maximum speed.

Parameters:

frequency - The new high speed frequency in Hz.

Throws:

CPUException - If there is an error during the configuration process.

java.lang.IllegalArgumentException - If frequency < 0.

See Also:

getHiSpeedFreq()

getHiSpeedFreq

public int getHiSpeedFreq()
                   throws CPUException

Gets the high speed frequency value at which to initially ramp when CPU load hits the high speed load value.

Returns:

The high speed frequency in Hz, -1 if the value could not be read.

Throws:

CPUException - If there is an error during the configuration process.

See Also:

setHiSpeedFreq(int)

setGoHiSpeedLoad

public void setGoHiSpeedLoad(int load)
                      throws CPUException

Sets the CPU load percentage at which to ramp to the intermediate 'High speed'.

Default is 85%.

Parameters:

load - The new CPU load percentage to ramp.

Throws:

CPUException - If there is an error during the configuration process.

java.lang.IllegalArgumentException - If load < 0 or if load > 100.

See Also:

getGoHiSpeedLoad()

getGoHiSpeedLoad

public int getGoHiSpeedLoad()
                     throws CPUException

Gets the CPU load percentage at which to ramp to the intermediate 'High speed'.

Default is 85%.

Returns:

The CPU load percentage to ramp, -1 if the value could not be read.

Throws:

CPUException - If there is an error during the configuration process.

See Also:

setGoHiSpeedLoad(int)

setAboveHiSpeedDelay

public void setAboveHiSpeedDelay(long delay)
                          throws CPUException

Sets the above high speed delay time in uS (10^-6 seconds). Once speed is set to high speed frequency, wait for this long before bumping speed higher in response to continued high load.

Default is 20000 uS.

Parameters:

delay - The new above high speed delay in uS.

Throws:

CPUException - If there is an error during the configuration process.

java.lang.IllegalArgumentException - If delay < 0 or if delay > MAX_ABOVE_HIGH_SPEED_DELAY.

See Also:

MAX_ABOVE_HIGH_SPEED_DELAY, getAboveHiSpeedDelay()

getAboveHiSpeedDelay

public long getAboveHiSpeedDelay()
                          throws CPUException

Gets the above high speed delay time in uS (10^-6 seconds). Once speed is set to high speed frequency, wait for this long before bumping speed higher in response to continued high load.

Default is 20000 uS.

Returns:

The above high speed delay in uS, -1 if the value could not be read.

Throws:

CPUException - If there is an error during the configuration process.

See Also:

setAboveHiSpeedDelay(long)

setTimerRate

public void setTimerRate(long rate)
                  throws CPUException

Sets the sample rate in uS (10^-6 seconds) for reevaluating CPU load when the system is not idle.

Default is 20000 uS.

Parameters:

rate - The new sample rate in uS.

Throws:

CPUException - If there is an error during the configuration process.

java.lang.IllegalArgumentException - If rate < 0 or if rate > MAX_TIMER_RATE.

See Also:

MAX_TIMER_RATE, getTimerRate()

getTimerRate

public long getTimerRate()
                  throws CPUException

Gets the sample rate in uS (10^-6 seconds) for reevaluating CPU load when the system is not idle.

Default is 20000 uS.

Returns:

The sample rate in uS, -1 if the value could not be read.

Throws:

CPUException - If there is an error during the configuration process.

See Also:

setTimerRate(long)

setTimerSlack

public void setTimerSlack(long time)
                   throws CPUException

Sets the maximum additional time in uS (10^-6 seconds) to defer handling the governor sampling timer beyond 'Timer rate' when running at speeds above the minimum. For platforms that consume additional power at idle when CPUs are running at speeds greater than minimum, this places an upper bound on how long the timer will be deferred prior to re-evaluating load and dropping speed.

For example, if 'Timer rate' is 20000uS and 'Timer slack' is 10000uS then timers will be deferred for up to 30ms when not at lowest speed. A value of -1 means defer timers indefinitely at all speeds.

Default is 80000 uS.

Parameters:

time - The new timer slack in uS.

Throws:

CPUException - If there is an error during the configuration process.

java.lang.IllegalArgumentException - If time < -1 or if time > MAX_TIMER_SLACK.

See Also:

MAX_TIMER_SLACK, getTimerSlack()

getTimerSlack

public long getTimerSlack()
                   throws CPUException

Gets the maximum additional time in uS (10^-6 seconds) to defer handling the governor sampling timer beyond 'Timer rate' when running at speeds above the minimum. For platforms that consume additional power at idle when CPUs are running at speeds greater than minimum, this places an upper bound on how long the timer will be deferred prior to re-evaluating load and dropping speed.

For example, if 'Timer rate' is 20000uS and 'Timer slack' is 10000uS then timers will be deferred for up to 30ms when not at lowest speed. A value of -1 means defer timers indefinitely at all speeds.

Default is 80000 uS.

Returns:

The timer slack in uS, -1 if the value could not be read.

Throws:

CPUException - If there is an error during the configuration process.

See Also:

setTimerSlack(long)

enableBoost

public void enableBoost()
                 throws CPUException

Enables the boost. When enabled, immediately boosts the speed of all CPUs to the high speed frequency until boost is disabled again. When disabled, allows CPU speeds to drop below the high speed frequency to load as usual.

Disabled by default.

Throws:

CPUException - If there is an error during the configuration process.

See Also:

disableBoost()

disableBoost

public void disableBoost()
                  throws CPUException

Disables the boost. When enabled, immediately boosts the speed of all CPUs to the high speed frequency until boost is disabled again. When disabled, allows CPU speeds to drop below the high speed frequency to load as usual.

Disabled by default.

Throws:

CPUException - If there is an error during the configuration process.

See Also:

enableBoost()

getBoost

public boolean getBoost()
                 throws CPUException

Returns whether boost is enabled or disabled. When boost is enabled, immediately boosts the speed of all CPUs to the high speed frequency until boost is disabled again. When disabled, allows CPU speeds to drop below the high speed frequency to load as usual.

Disabled by default.

Returns:

true if boost is enabled, false if it is disabled.

Throws:

CPUException - If there is an error during the configuration process.

See Also:

enableBoost(), disableBoost()

setBoostPulseDuration

public void setBoostPulseDuration(long time)
                           throws CPUException

Sets the length of time in uS (10^-6 seconds) to hold CPU speed at high speed frequency on a write boost pulse (@see #CPUManager.boostPulse()), before allowing speed to drop according to load as usual.

Default is 80000 uS.

Parameters:

time - The length in uS of the pulse duration.

Throws:

CPUException - If there is an error during the configuration process.

java.lang.IllegalArgumentException - If time < 0 or if time > MAX_BOOSTPULSE_DURATION.

See Also:

MAX_BOOSTPULSE_DURATION, getBoostPulseDuration(), CPUManager.boostPulse()

getBoostPulseDuration

public long getBoostPulseDuration()
                           throws CPUException

Gets the length of time to hold CPU speed in uS (10^-6 seconds) at high speed frequency on a boost pulse (@see #CPUManager.boostPulse()), before allowing speed to drop according to load as usual.

Default is 80000 uS.

Returns:

The length of time to hold CPU speed in uS at high speed frequency on a boost pulse, -1 if the value could not be read.

Throws:

CPUException - If there is an error during the configuration process.

See Also:

setBoostPulseDuration(long), CPUManager.boostPulse()