org.jikesrvm.runtime

Class Time

java.lang.Object

org.jikesrvm.runtime.Time

public class Time
extends Object

Primitives from which to build interval and absolute timers.

Field Summary

Fields

Modifier and Type	Field and Description
private static long	bootTime boot time in milliseconds

Constructor Summary

Constructors

Constructor and Description
Time()

Method Summary

Modifier and Type	Method and Description
static void	boot()
static long	bootTime()
static long	currentTimeMillis()
static long	cycles() Return the value of a hardware cycle counter (RDTSC on IA32, time base register on PPC).
static double	nanosToMillis(long c) Convert a long representing a time in nanoseconds into a double representing the same time in milliseconds.
static double	nanosToSecs(long nanos)
static long	nanoTime() Same semantics as java.lang.System.nanoTime(); This (or java.lang.System.nanoTime) is the preferred API for VM internal timing functions.
static long	secsToNanos(double secs)

Methods inherited from class java.lang.Object

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

Field Detail

bootTime

private static long bootTime

boot time in milliseconds

Constructor Detail

Time

public Time()

Method Detail

boot

public static void boot()

nanosToMillis

public static double nanosToMillis(long c)

Convert a long representing a time in nanoseconds into a double representing the same time in milliseconds.

Parameters:

c - a time in nanoseconds

Returns:

c converted to milliseconds

cycles

public static long cycles()

Return the value of a hardware cycle counter (RDTSC on IA32, time base register on PPC). This is a very cheap, but also unreliable "timing" mechanism. There is absolutely no guarantee that the values returned from this method will either by monotonic (i.e., "time" can go backwards) or smooth ("time" can appear to move at a variable rate). This method should only be used for approximate timing in frequently executed code. We intentionally do not provide an API for converting from cycles to seconds because the conversion cannot be reliably supported on all of our platforms.

Returns:

the value of the hardware cycle counter

nanoTime

public static long nanoTime()

Same semantics as java.lang.System.nanoTime(); This (or java.lang.System.nanoTime) is the preferred API for VM internal timing functions.

Returns:

a monotonic timer value in nanoseconds.

currentTimeMillis

public static long currentTimeMillis()

Returns:

current time in milliseconds (epoch Jan 1 1970).

nanosToSecs

public static double nanosToSecs(long nanos)

secsToNanos

public static long secsToNanos(double secs)

bootTime

public static long bootTime()