Package org.apache.hadoop.util

Class CpuTimeTracker

java.lang.Object

org.apache.hadoop.util.CpuTimeTracker

@Private
@Unstable
public class CpuTimeTracker
extends java.lang.Object

Utility for sampling and computing CPU usage.

Field Summary

Fields

Modifier and Type	Field	Description
static int	UNAVAILABLE

Constructor Summary

Constructors

Constructor	Description
CpuTimeTracker(long jiffyLengthInMillis)

Method Summary

Modifier and Type	Method	Description
float	getCpuTrackerUsagePercent()	Return percentage of cpu time spent over the time since last update.
long	getCumulativeCpuTime()	Obtain the cumulative CPU time since the system is on.
java.lang.String	toString()
void	updateElapsedJiffies(java.math.BigInteger elapsedJiffies, long newTime)	Apply delta to accumulators.

Methods inherited from class java.lang.Object

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

Field Detail

UNAVAILABLE

public static final int UNAVAILABLE

See Also:

Constant Field Values

Constructor Detail

CpuTimeTracker

public CpuTimeTracker(long jiffyLengthInMillis)

Method Detail

getCpuTrackerUsagePercent

public float getCpuTrackerUsagePercent()

Return percentage of cpu time spent over the time since last update. CPU time spent is based on elapsed jiffies multiplied by amount of time for 1 core. Thus, if you use 2 cores completely you would have spent twice the actual time between updates and this will return 200%.

Returns:

Return percentage of cpu usage since last update, UNAVAILABLE if there haven't been 2 updates more than minimumTimeInterval apart

getCumulativeCpuTime

public long getCumulativeCpuTime()

Obtain the cumulative CPU time since the system is on.

Returns:

cumulative CPU time in milliseconds

updateElapsedJiffies

public void updateElapsedJiffies(java.math.BigInteger elapsedJiffies,
                                 long newTime)

Apply delta to accumulators.

Parameters:

elapsedJiffies - updated jiffies

newTime - new sample time

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object