Package com.digi.android.system.cpu

Class GovernorCommonBase

java.lang.Object

com.digi.android.system.cpu.Governor

com.digi.android.system.cpu.GovernorCommonBase

Direct Known Subclasses:

GovernorConservative, GovernorOnDemand

public abstract class GovernorCommonBase
extends Governor

Represents an abstract governor class with some configuration parameters already implemented. These parameters are common for some governors, so they must extend this class in order to include them.

This governor class cannot be instantiated.

Field Summary

Fields

Modifier and Type	Field	Description
static long	MAX_SAMPLING_RATE	Maximum sampling rate: microseconds.
static long	MIN_SAMPLING_RATE	Minimum sampling rate: microseconds.

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

governorType, manager, PATH_GOVERNOR_SETTINGS

Method Summary

Modifier and Type	Method	Description
void	disableIgnoreNiceLoad()	Enables the ignore nice load parameter.
void	enableIgnoreNiceLoad()	Disables the ignore nice load parameter.
boolean	getIgnoreNiceLoad()	Gets whether the ignore nice load parameter is enabled or disabled.
long	getMinSamplingRate()	Deprecated. This functionality is not available for kernel 4.14 or higher. In this case the method returns MIN_SAMPLING_RATE.
int	getSamplingDownFactor()	Gets the sampling down factor.
protected abstract int	getSamplingDownFactorMaxValue()	Returns the maximum limit for the sampling down factor.
long	getSamplingRate()	Returns the sampling rate in uS.
int	getUpThreshold()	Gets the up threshold percentage.
protected abstract int	getUpThresholdMinValue()	Returns the minimum limit for the up threshold percentage.
void	setSamplingDownFactor(int factor)	Sets the sampling down factor.
void	setSamplingRate(long rate)	Sets the sampling rate in uS.
void	setUpThreshold(int threshold)	Sets the up threshold percentage.

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

getGovernorType, getSettingPath, getTag, readFile, writeFile

Methods inherited from class java.lang.Object

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

Field Detail

MAX_SAMPLING_RATE

public static final long MAX_SAMPLING_RATE

Maximum sampling rate: microseconds.

See Also:

Constant Field Values

MIN_SAMPLING_RATE

public static final long MIN_SAMPLING_RATE

Minimum sampling rate: microseconds.

This is used for kernels 4.14 or higher.

See Also:

Constant Field Values

Method Detail

setSamplingRate

public void setSamplingRate(long rate)
                     throws CPUException

Sets the sampling rate in uS. It is how often the kernel will look at the CPU usage and to make decisions on what to do about the frequency.

Parameters:

rate - The sampling rate in uS (10^-6 seconds)

Throws:

java.lang.IllegalArgumentException - If rate < MIN_SAMPLING_RATE and kernel 4.14 or higher, if {@code rate < getMinSamplingRate()) and previous kernel versions, or if {@code rate > MAX_SAMPLING_RATE}.

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

See Also:

MAX_SAMPLING_RATE, MIN_SAMPLING_RATE, getMinSamplingRate(), getSamplingRate()

getSamplingRate

public long getSamplingRate()
                     throws CPUException

Returns the sampling rate in uS. It is how often the kernel looks at the CPU usage and to make decisions on what to do about the frequency.

Returns:

The sampling rate 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:

getMinSamplingRate(), setSamplingRate(long)

getMinSamplingRate

@Deprecated
public long getMinSamplingRate()
                        throws CPUException

Deprecated. This functionality is not available for kernel 4.14 or higher. In this case the method returns MIN_SAMPLING_RATE.

Returns the minimum sampling rate in uS.

The sampling rate is limited by the HW transition latency:

1. transition_latency * 100

Or by kernel restrictions:

1. If CONFIG_NO_HZ is set, the limit is 10ms fixed.
2. If CONFIG_NO_HZ is not set or nohz=off boot parameter is used, the limits depend on the CONFIG_HZ option:
   1. HZ=1000: min=20000us (20ms)
   2. HZ=250: min=80000us (80ms)
   3. HZ=100: min=200000us (200ms)

The highest value of kernel and HW latency restrictions is shown and used as the minimum sampling rate.

Returns:

The minimum sampling rate in uS (10^-6 seconds), -1 if the value could not be read. For kernel 4.14 or higher it always returns MIN_SAMPLING_RATE.

Throws:

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

See Also:

getSamplingRate(), setSamplingRate(long)

setUpThreshold

public void setUpThreshold(int threshold)
                    throws CPUException

Sets the up threshold percentage. Defines what the average CPU usage between the samplings of 'Sampling rate' needs to be for the kernel to make a decision on whether it should increase the frequency.

For example when it is set to its default value of '95' it means that between the checking intervals the CPU needs to be on average more than 95% in use to then decide that the CPU frequency needs to be increased.

Parameters:

threshold - The up threshold percentage.

Throws:

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

java.lang.IllegalArgumentException - If threshold < getUpThresholdMinValue() or if threshold > 100.

See Also:

getUpThreshold(), getUpThresholdMinValue()

getUpThreshold

public int getUpThreshold()
                   throws CPUException

Gets the up threshold percentage. Gets the average CPU usage between the samplings of 'Sampling rate' needs to be for the kernel to make a decision on whether it should increase the frequency.

Returns:

The up threshold percentage, -1 if the value could not be read.

Throws:

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

See Also:

setUpThreshold(int)

enableIgnoreNiceLoad

public void enableIgnoreNiceLoad()
                          throws CPUException

Disables the ignore nice load parameter. When it is disabled (default), all processes are counted towards the 'CPU usage' value.

Throws:

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

See Also:

disableIgnoreNiceLoad(), getIgnoreNiceLoad()

disableIgnoreNiceLoad

public void disableIgnoreNiceLoad()
                           throws CPUException

Enables the ignore nice load parameter. When it is enabled, the processes that are run with a 'nice' value will not count in the overall usage calculation.

Throws:

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

See Also:

enableIgnoreNiceLoad(), getIgnoreNiceLoad()

getIgnoreNiceLoad

public boolean getIgnoreNiceLoad()
                          throws CPUException

Gets whether the ignore nice load parameter is enabled or disabled. When it is disabled (default), all processes are counted towards the 'CPU usage' value. When it is enabled, the processes that are run with a 'nice' value will not count in the overall usage calculation.

Returns:

true if processes that are running with a 'nice' value are ignored, false otherwise.

Throws:

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

See Also:

enableIgnoreNiceLoad(), disableIgnoreNiceLoad()

setSamplingDownFactor

public void setSamplingDownFactor(int factor)
                           throws CPUException

Sets the sampling down factor. This parameter controls the rate at which the kernel makes a decision on when to decrease the frequency while running at top speed. When set to 1 (the default) decisions to reevaluate load are made at the same interval regardless of current clock speed. But when set to greater than 1 (e.g. 10) it acts as a multiplier for the scheduling interval for reevaluating load when the CPU is at its top speed due to high load.

Parameters:

factor - The new sampling down factor.

Throws:

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

java.lang.IllegalArgumentException - If factor < 1 or if factor > getSamplingDownFactorMaxValue().

See Also:

getSamplingDownFactor(), getSamplingDownFactorMaxValue()

getSamplingDownFactor

public int getSamplingDownFactor()
                          throws CPUException

Gets the sampling down factor. This parameter controls the rate at which the kernel makes a decision on when to decrease the frequency while running at top speed. When set to 1 (the default) decisions to reevaluate load are made at the same interval regardless of current clock speed. But when set to greater than 1 (e.g. 10) it acts as a multiplier for the scheduling interval for reevaluating load when the CPU is at its top speed due to high load.

Returns:

The sampling down factor, -1 if the value could not be read.

Throws:

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

See Also:

setSamplingDownFactor(int)

getSamplingDownFactorMaxValue

protected abstract int getSamplingDownFactorMaxValue()

Returns the maximum limit for the sampling down factor.

Returns:

the maximum limit for the sampling down factor.

getUpThresholdMinValue

protected abstract int getUpThresholdMinValue()
                                       throws CPUException

Returns the minimum limit for the up threshold percentage.

Returns:

the minimum limit for the up threshold.

Throws:

CPUException - If there is an error while calculating the minimum limit.