A convenience class to do code profiling.
//package com.ryanm.util;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Collections;
/**
* A convenience class to do code profiling.
*
* @author Keith Woodward
*/
public class CodeTimer {
private static DecimalFormat fourDP = new DecimalFormat("0.####");
private static DecimalFormat percent = new DecimalFormat("0.#%");
/**
* How long a call to {@link #tick(String)} takes
*/
private static long SELF_TIME;
private static final long NANOS_IN_A_SECOND = 1000000000;
private static final long NANOS_IN_A_MILLISECOND = 1000000;
static {
recalibrate(10000);
}
/**
* The name of this {@link CodeTimer}, to identify the output
*/
public final String name;
/**
* Names of intervals
*/
private String[] intervalNames = new String[5];
/**
* Sum of interval durations
*/
private long[] intervalDurationSums = new long[intervalNames.length];
/**
* The index of the current interval
*/
private int intervalIndex;
/**
* The time of the last call to {@link #tick(String)}
*/
private long lastClickTime;
/**
* Count of timing periods
*/
private int periodCount = 0;
private boolean periodStarted = false;
private long periodStartTime;
/**
* Sum of period durations
*/
private long periodDurationSum = 0;
/**
* Defaults to <code>true</code>
*/
public boolean enabled = true;
private long lastPrintOutNanos = System.nanoTime();
/**
* The number of seconds between prints, defaults to 5
*/
public int printFrequencySeconds = 5;
/**
* The level of information printed for the total time spent in a profiling
* period
*/
public Output period;
/**
* The level of information printed for time taken in intervals
*/
public Output interval;
/**
* @param name
* A name for this {@link CodeTimer}, so as to identify the
* output
* @param period
* output for profiling period duration. May not be null
* @param interval
* output for interval durations, May not be null
*/
public CodeTimer(String name, Output period, Output interval) {
this.name = name;
this.period = period;
this.interval = interval;
}
/**
* Call to start a profiling period, or to start an interval in an open
* period
*
* @param name
* A helpful name for this interval. Makes it easy to find what
* bit of code you're measuring
*/
public void tick(String name) {
if (enabled) {
long clickTime = System.nanoTime();
if (!periodStarted) {
periodStarted = true;
periodStartTime = clickTime;
intervalNames[0] = name;
} else {
long duration = clickTime - lastClickTime;
intervalDurationSums[intervalIndex] += duration;
intervalIndex++;
if (intervalIndex >= intervalNames.length) {
intervalNames = ArrayUtil.grow(intervalNames);
intervalDurationSums = ArrayUtil.grow(intervalDurationSums);
}
intervalNames[intervalIndex] = name;
}
lastClickTime = clickTime;
}
}
/**
* Call to end a profiling period, and print the results if
* {@link #printFrequencySeconds} have passed since we last printed
*/
public void lastTick() {
lastTick(System.nanoTime() - lastPrintOutNanos > printFrequencySeconds
* NANOS_IN_A_SECOND);
}
/**
* Call to end a profiling period
*
* @param print
* <code>true</code> to print results, <code>false</code> no to
*/
public void lastTick(boolean print) {
if (enabled) {
long clickTime = System.nanoTime();
long intervalDuration = clickTime - lastClickTime;
intervalDurationSums[intervalIndex] += intervalDuration;
intervalIndex = 0;
long periodDuration = clickTime - periodStartTime;
periodDurationSum += periodDuration;
periodCount++;
periodStarted = false;
if (print) {
System.out.println(name + " period "
+ period.format(periodDurationSum, periodCount));
long perDur = periodDurationSum / periodCount;
for (int i = 0; i < intervalNames.length
&& intervalNames[i] != null; i++) {
float intDur = intervalDurationSums[i] / periodCount;
float p = intDur / perDur;
System.out.println("\t"
+ intervalNames[i]
+ "\t"
+ percent.format(p)
+ "\t"
+ interval.format(intervalDurationSums[i],
periodCount));
}
for (int i = 0; i < intervalDurationSums.length; i++) {
intervalDurationSums[i] = 0;
intervalNames[i] = null;
}
periodDurationSum = 0;
periodCount = 0;
lastPrintOutNanos = clickTime;
}
}
}
/**
* Calibrates the timer for the machine
*
* @param numTests
* 10000 might be about right
*/
public static void recalibrate(int numTests) {
boolean print = false;
CodeTimer codeTimer = new CodeTimer("calibrate", null, null);
// warm the JIT
for (int i = 0; i < 1024; i++) {
codeTimer.tick("foo");
codeTimer.lastTick(false);
}
// find how out long it takes to call click(), so that time can
// be accounted for
ArrayList<Long> selfTimeObservations = new ArrayList<Long>(numTests);
for (int i = 0; i < numTests; i++) {
long nanoSelfTime = -(System.nanoTime() - System.nanoTime());
codeTimer.tick("foo");
long t0 = System.nanoTime();
codeTimer.tick("bar");
long t1 = System.nanoTime();
codeTimer.tick("baz");
codeTimer.lastTick(false);
long currentSelfTime = t1 - t0 - nanoSelfTime;
if (print) {
System.out
.println("calibrating : currentSelfTime == "
+ currentSelfTime + ", nanoSelfTime == "
+ nanoSelfTime);
}
selfTimeObservations.add(new Long(currentSelfTime));
}
// sort the times
Collections.sort(selfTimeObservations);
if (print) {
for (int i = 0; i < selfTimeObservations.size(); i++) {
System.out
.println("calibrating : selfTimeObservations.get(i) == "
+ selfTimeObservations.get(i));
}
}
// cut out the slowest 5% which are assumed to be outliers
for (int i = 0; i < (int) (numTests * 0.05); i++) {
selfTimeObservations.remove(0);
}
// cut out the fastest 5% which are assumed to be outliers
for (int i = 0; i < (int) (numTests * 0.05); i++) {
selfTimeObservations.remove(selfTimeObservations.size() - 1);
}
if (print) {
System.out
.println("calibrating : Slimmed list: selfTimeObservations.size() == "
+ selfTimeObservations.size());
for (int i = 0; i < selfTimeObservations.size(); i++) {
System.out
.println("calibrating : selfTimeObservations.get(i) == "
+ selfTimeObservations.get(i));
}
}
// find the average
long sumOfSelfTimes = 0;
for (int i = 0; i < selfTimeObservations.size(); i++) {
sumOfSelfTimes += selfTimeObservations.get(i).longValue();
}
SELF_TIME = sumOfSelfTimes / selfTimeObservations.size();
if (print) {
System.out.println("calibrating : SELF_TIME == " + SELF_TIME);
}
}
/**
* Time unit that is printed
*
* @author ryanm
*/
public enum Output {
/**
* Second-level granularity
*/
Seconds {
@Override
public String format(long totalNanos, long count) {
double avTotalSeconds = (double) totalNanos
/ (count * NANOS_IN_A_SECOND);
return fourDP.format(avTotalSeconds) + "s";
}
},
/**
* Millisecond-level granularity
*/
Millis {
@Override
public String format(long totalNanos, long count) {
double avTotalMillis = (double) totalNanos
/ (count * NANOS_IN_A_MILLISECOND);
return fourDP.format(avTotalMillis) + "ms";
}
},
/**
* Nanosecond-level granularity
*/
Nanos {
@Override
public String format(long totalNanos, long count) {
double avTotalNanos = (double) totalNanos / count;
return fourDP.format(avTotalNanos) + "ns";
}
};
/**
* @param totalNanos
* The sum of some number of measurements
* @param count
* The number of measurements
* @return A string describing the average time
*/
public abstract String format(long totalNanos, long count);
};
}
class ArrayUtil {
/**
* Doubles the size of an array
*
* @param in
* @return The new array
*/
public static String[] grow(String[] in) {
String[] na = new String[in.length * 2];
System.arraycopy(in, 0, na, 0, in.length);
return na;
}
/**
* Doubles the size of an array
*
* @param in
* @return The new array
*/
public static long[] grow(long[] in) {
long[] na = new long[in.length * 2];
System.arraycopy(in, 0, na, 0, in.length);
return na;
}
/**
* Doubles the size of an array
*
* @param in
* @return The new array
*/
public static int[] grow(int[] in) {
int[] na = new int[in.length * 2];
System.arraycopy(in, 0, na, 0, in.length);
return na;
}
}
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