Package org.wikidata.wdtk.util

Class Timer

java.lang.Object
org.wikidata.wdtk.util.Timer
public class Timer extends Object
Class for keeping CPU and system times. Timers measure wall clock and/or CPU times (for specific threads). They can be started and stopped. Times between these two methods will be recorded and (when starting and stopping more than once) added up to total times. The number of start-stop measurements is recorded, and one can also query the average times. Finally, a timer can be reset. There are two main ways of accessing timers: by creating a Timer object directly or by using a global registry of timers. Registered timers are identified by their string name and thread id. The global registry is useful since it makes it much easier to re-integrate measurements taken in many threads. They also free the caller of the burden of keeping a reference to the Timer. The code in this file was adapted from the ElkTimer class of the ELK reasoner, with contributions from Yevgeny Kasakov and Pavel Klinov.
Author:
Markus Kroetzsch

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    RECORD_ALL
    Flag for indicating that all supported times should be taken.
    static final int
    RECORD_CPUTIME
    Flag for indicating that CPU time should be taken.
    static final int
    RECORD_NONE
    Flag for indicating that no times should be taken (just count runs).
    static final int
    RECORD_WALLTIME
    Flag for indicating that wall clock time should be taken.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Timer(String name, int todoFlags)
    Constructor.
    Timer(String name, int todoFlags, long threadId)
    Constructor.

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    equals(Object obj)
     
    long
    getAvgCpuTime()
    Return the average CPU time across all measurements.
    long
    getAvgWallTime()
    Return the average wall clock time across all measurements.
    String
    getName()
    Get the string name of the timer.
    static Timer
    getNamedTimer(String timerName)
    Get a timer of the given string name that takes all possible times (todos) for the current thread.
    static Timer
    getNamedTimer(String timerName, int todoFlags)
    Get a timer of the given string name and todos for the current thread.
    static Timer
    getNamedTimer(String timerName, int todoFlags, long threadId)
    Get a timer of the given string name for the given thread.
    static Timer
    getNamedTotalTimer(String timerName)
    Collect the total times measured by all known named timers of the given name.
    long
    getThreadId()
    Get the ID of the thread for which this timer was created.
    long
    getTotalCpuTime()
    Get the total recorded CPU time in nanoseconds.
    long
    getTotalWallTime()
    Get the total recorded wall clock time in nanoseconds.
    int
    hashCode()
     
    boolean
    isRunning()
    Return true if the timer is running.
    void
    reset()
    Stop the timer (if running) and reset all recorded values.
    static void
    resetNamedTimer(String timerName)
    Reset a timer of the given string name for all todos and the current thread.
    static void
    resetNamedTimer(String timerName, int todoFlags)
    Reset a timer of the given string name for the current thread.
    static void
    resetNamedTimer(String timerName, int todoFlags, long threadId)
    Reset a timer of the given string name for the given thread.
    void
    start()
    Start the timer.
    static void
    startNamedTimer(String timerName)
    Start a timer of the given string name for all todos and the current thread.
    static void
    startNamedTimer(String timerName, int todoFlags)
    Start a timer of the given string name for the current thread.
    static void
    startNamedTimer(String timerName, int todoFlags, long threadId)
    Start a timer of the given string name for the current thread.
    long
    stop()
    Stop the timer and record the times that have passed since its start.
    static long
    stopNamedTimer(String timerName)
    Stop a timer of the given string name for all todos and the current thread.
    static long
    stopNamedTimer(String timerName, int todoFlags)
    Stop a timer of the given string name for the current thread.
    static long
    stopNamedTimer(String timerName, int todoFlags, long threadId)
    Stop a timer of the given string name for the given thread.
    String
    toString()
    The implementation of toString() generates a summary of the times recorded so far.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • RECORD_NONE

      public static final int RECORD_NONE
      Flag for indicating that no times should be taken (just count runs).
      See Also:

    • RECORD_CPUTIME

      public static final int RECORD_CPUTIME
      Flag for indicating that CPU time should be taken.
      See Also:

    • RECORD_WALLTIME

      public static final int RECORD_WALLTIME
      Flag for indicating that wall clock time should be taken.
      See Also:

    • RECORD_ALL

      public static final int RECORD_ALL
      Flag for indicating that all supported times should be taken.
      See Also:

  • Constructor Details

    • Timer

      public Timer(String name, int todoFlags, long threadId)
      Constructor. Every timer is identified by three things: a string name, an integer for flagging its tasks (todos), and a thread id (long). Tasks can be flagged by a disjunction of constants like RECORD_CPUTIME and RECORD_WALLTIME. Only times for which an according flag is set will be recorded. The thread id can be the actual id of the thread that is measured, or 0 (invalid id) to not assign the timer to any thread. In this case, no CPU time measurement is possible since Java does not allow us to measure the total CPU time across all threads.
      Parameters:
      name - a string that identifies the timer
      todoFlags - flags to define what the timer will measure
      threadId - the id of the thread for measuring CPU time or 0 if not measuring

    • Timer

      public Timer(String name, int todoFlags)
      Constructor. Same as Timer(String, int, long), but using the current thread instead of a freely specified thread.
      Parameters:
      name - a string that identifies the timer
      todoFlags - flags to define what the timer will measure

  • Method Details

    • getName

      public String getName()
      Get the string name of the timer.
      Returns:
      string name

    • getThreadId

      public long getThreadId()
      Get the ID of the thread for which this timer was created.
      Returns:
      thread ID

    • isRunning

      public boolean isRunning()
      Return true if the timer is running.
      Returns:
      true if running

    • getTotalCpuTime

      public long getTotalCpuTime()
      Get the total recorded CPU time in nanoseconds.
      Returns:
      recorded CPU time in nanoseconds

    • getAvgCpuTime

      public long getAvgCpuTime()
      Return the average CPU time across all measurements.
      Returns:
      the average CPU time across all measurements

    • getTotalWallTime

      public long getTotalWallTime()
      Get the total recorded wall clock time in nanoseconds.
      Returns:
      recorded wall time in nanoseconds

    • getAvgWallTime

      public long getAvgWallTime()
      Return the average wall clock time across all measurements.
      Returns:
      the average wall clock time across all measurements

    • start

      public void start()
      Start the timer.

    • reset

      public void reset()
      Stop the timer (if running) and reset all recorded values.

    • stop

      public long stop()
      Stop the timer and record the times that have passed since its start. The times that have passed are added to the internal state and can be retrieved with getTotalCpuTime() etc. If CPU times are recorded, then the method returns the CPU time that has passed since the timer was last started; otherwise -1 is returned.
      Returns:
      CPU time that the timer was running, or -1 if timer not running or CPU time unavailable for other reasons

    • toString

      public String toString()
      The implementation of toString() generates a summary of the times recorded so far. If the timer is still running, then it will not be stopped to add the currently measured time to the output but a warning will added.
      Overrides:
      toString in class Object
      Returns:
      string description of the timer results and state

    • startNamedTimer

      public static void startNamedTimer(String timerName)
      Start a timer of the given string name for all todos and the current thread. If no such timer exists yet, then it will be newly created.
      Parameters:
      timerName - the name of the timer

    • startNamedTimer

      public static void startNamedTimer(String timerName, int todoFlags)
      Start a timer of the given string name for the current thread. If no such timer exists yet, then it will be newly created.
      Parameters:
      timerName - the name of the timer
      todoFlags -

    • startNamedTimer

      public static void startNamedTimer(String timerName, int todoFlags, long threadId)
      Start a timer of the given string name for the current thread. If no such timer exists yet, then it will be newly created.
      Parameters:
      timerName - the name of the timer
      todoFlags -
      threadId - of the thread to track, or 0 if only system clock should be tracked

    • stopNamedTimer

      public static long stopNamedTimer(String timerName)
      Stop a timer of the given string name for all todos and the current thread. If no such timer exists, -1 will be returned. Otherwise the return value is the CPU time that was measured.
      Parameters:
      timerName - the name of the timer
      Returns:
      CPU time if timer existed and was running, and -1 otherwise

    • stopNamedTimer

      public static long stopNamedTimer(String timerName, int todoFlags)
      Stop a timer of the given string name for the current thread. If no such timer exists, -1 will be returned. Otherwise the return value is the CPU time that was measured.
      Parameters:
      timerName - the name of the timer
      todoFlags -
      Returns:
      CPU time if timer existed and was running, and -1 otherwise

    • stopNamedTimer

      public static long stopNamedTimer(String timerName, int todoFlags, long threadId)
      Stop a timer of the given string name for the given thread. If no such timer exists, -1 will be returned. Otherwise the return value is the CPU time that was measured.
      Parameters:
      timerName - the name of the timer
      todoFlags -
      threadId - of the thread to track, or 0 if only system clock should be tracked
      Returns:
      CPU time if timer existed and was running, and -1 otherwise

    • resetNamedTimer

      public static void resetNamedTimer(String timerName)
      Reset a timer of the given string name for all todos and the current thread. If no such timer exists yet, then it will be newly created.
      Parameters:
      timerName - the name of the timer

    • resetNamedTimer

      public static void resetNamedTimer(String timerName, int todoFlags)
      Reset a timer of the given string name for the current thread. If no such timer exists yet, then it will be newly created.
      Parameters:
      timerName - the name of the timer
      todoFlags -

    • resetNamedTimer

      public static void resetNamedTimer(String timerName, int todoFlags, long threadId)
      Reset a timer of the given string name for the given thread. If no such timer exists yet, then it will be newly created.
      Parameters:
      timerName - the name of the timer
      todoFlags -
      threadId - of the thread to track, or 0 if only system clock should be tracked

    • getNamedTimer

      public static Timer getNamedTimer(String timerName)
      Get a timer of the given string name that takes all possible times (todos) for the current thread. If no such timer exists yet, then it will be newly created.
      Parameters:
      timerName - the name of the timer
      Returns:
      timer

    • getNamedTimer

      public static Timer getNamedTimer(String timerName, int todoFlags)
      Get a timer of the given string name and todos for the current thread. If no such timer exists yet, then it will be newly created.
      Parameters:
      timerName - the name of the timer
      todoFlags -
      Returns:
      timer

    • getNamedTimer

      public static Timer getNamedTimer(String timerName, int todoFlags, long threadId)
      Get a timer of the given string name for the given thread. If no such timer exists yet, then it will be newly created.
      Parameters:
      timerName - the name of the timer
      todoFlags -
      threadId - of the thread to track, or 0 if only system clock should be tracked
      Returns:
      timer

    • getNamedTotalTimer

      public static Timer getNamedTotalTimer(String timerName)
      Collect the total times measured by all known named timers of the given name. This is useful to add up times that were collected across separate threads.
      Parameters:
      timerName -
      Returns:
      timer

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object