org.cometd.benchmark

Class SystemTimer

java.lang.Object

org.cometd.benchmark.SystemTimer

public class SystemTimer
extends Object

Detects and reports the timer resolution of the current running platform.

Unfortunately, Thread.sleep(long) on many platforms has a resolution of 1 ms or even of 10 ms, so calling Thread.sleep(2) often results in a 10 ms sleep.
The same applies for Thread.sleep(long, int) and Object.wait(long, int): they are not accurate, especially on virtualized platforms (like Amazon EC2, where the resolution can be as high as 64 ms).

System.nanoTime() is precise enough, but we would need to loop continuously checking the nano time until the sleep period is elapsed; to avoid busy looping pegging the CPUs, Thread.yield() is called to attempt to reduce the CPU load.

Method Summary

Methods

Modifier and Type	Method and Description
static SystemTimer	detect()
long	getEmulatedResolution()
long	getNativeResolution()
static void	main(String[] args)
void	sleep(long micros)
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

getNativeResolution

public long getNativeResolution()

getEmulatedResolution

public long getEmulatedResolution()

sleep

public void sleep(long micros)

toString

public String toString()

Overrides:

toString in class Object

detect

public static SystemTimer detect()

main

public static void main(String[] args)