Class ProcessStatus

java.lang.Object
  ProcessStatus

public class ProcessStatus
extends Object

Represents status (memory and CPU usage) information about a process.

Not all fields are available from the system directly, some fields are computed using other fields (e.g. in Linux swap is computed from difference of virtual and resident memory, exitTime is the same as timestamp, on Windows virtual memory includes swap usage which may contain redundancies). Peak information on some platforms (e.g. Linux) is updated as being sampled, so make sure the peaks are reset when a different process is sampled.

timestamp, startTime and exitTime are relative to OS-specific Epoch and should be used in relation to each other, hence no normalization is done here. A few Epoch interpretations:

• Epoch in Linux: January 1, 1970 00:00:00 UTC.
• Epoch in Win32: January 1, 1601 00:00:00 UTC.

Sometimes the information gathering may fail (e.g. process exits and information is no longer available), then the fields should remain untouched preserving last sample results from the last successful call.

See Also:

SystemManager.fetchProcessStatus(int, ProcessStatus)

Field Summary

long	exitTime Microseconds when this process exited since Epoch If the information is not available (process did not exit yet) then it contains the current timestamp.
int	pageFaultCount Number of (major) page faults.
long	residentPeak Maximum peak usage of resident memory (working set) in bytes.
long	residentSize Resident memory (working set) size in bytes.
long	systemTime CPU time spent on executing the process in kernel space in microseconds.
long	startTime Microseconds when this process started since Epoch.
long	swapPeak Maximum peak usage of swap space (memory on disk) in bytes.
long	swapSize Usage of swap space (memory on disk) in bytes.
long	timestamp Microseconds since Epoch until this information has been updated.
long	userTime CPU time spent on executing the process tasks in micro seconds.
long	virtualPeak Maximum peak virtual memory size in bytes.
long	virtualSize Virtual memory size in bytes.

Constructor Summary

ProcessStatus()

Method Summary

String	getMemory() Compose a user-friendly string representation about memory peaks.
String	getTimes() Compose a user-friendly string representation of timing information.
void	printInKB()
void	resetPeaks() Resets the peak status information.

Methods inherited from class java.lang.Object

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

Field Detail

pageFaultCount

public int pageFaultCount

Number of (major) page faults. Page faults are triggered when some process memory has been swapped out to disk and the requested memory page is not in the physical memory anymore (consequently OS loads those pages back into memory).

virtualSize

public long virtualSize

Virtual memory size in bytes. This is a memory size lying in physical (resident) memory plus some memory in swap space.

See Also:

residentSize, swapSize

virtualPeak

public long virtualPeak

Maximum peak virtual memory size in bytes. The maximum virtual memory observed. The observation is OS-dependent: some OSes (e.g. Windows) maintain this information themselves, while on others (e.g. Linux) the information is sampled only during SystemManager.fetchProcessStatus calls, hence may be inacurate. On Unix more precise information can be extracted from processes that are started as children.

See Also:

virtualSize

residentSize

public long residentSize

Resident memory (working set) size in bytes. This is the size of physical memory that process occupies at the moment of sampling.

residentPeak

public long residentPeak

Maximum peak usage of resident memory (working set) in bytes.

See Also:

residentSize

swapSize

public long swapSize

Usage of swap space (memory on disk) in bytes. This memory may or may not be in operating memory, i.e. OS may have chosen to copy some memory pages to swap space but not yet released from physical memory (typical Windows behavior). As a consequence on some operating systems swap and resident memory sum may exceed virtual memory.

See Also:

virtualSize

swapPeak

public long swapPeak

Maximum peak usage of swap space (memory on disk) in bytes. The memory may or may not be in operating memory.

See Also:

swapSize

userTime

public long userTime

CPU time spent on executing the process tasks in micro seconds. (note: calculated from Windows API, which is in 100ns units) (note: Windows also provide creation and exit times, which could be used to calculate the time duration of process life).

systemTime

public long systemTime

CPU time spent on executing the process in kernel space in microseconds. (note: calculated from Windows API, which is in 100ns units)

timestamp

public long timestamp

Microseconds since Epoch until this information has been updated.

startTime

public long startTime

Microseconds when this process started since Epoch.

exitTime

public long exitTime

Microseconds when this process exited since Epoch If the information is not available (process did not exit yet) then it contains the current timestamp.

Constructor Detail

ProcessStatus

public ProcessStatus()

Method Detail

resetPeaks

public void resetPeaks()

Resets the peak status information. Use this method when sampling is switched over a different process.

printInKB

public void printInKB()

getTimes

public String getTimes()

Compose a user-friendly string representation of timing information.

Returns:

string representing timing status.

See Also:

getMemory()

getMemory

public String getMemory()

Compose a user-friendly string representation about memory peaks.

Returns:

string representing memory peaks.

See Also:

getTimes(), resetPeaks()