com.google.gwt.dev.util.PerfCounter Maven / Gradle / Ivy
/*
* Copyright 2009 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.dev.util;
import com.google.gwt.thirdparty.guava.common.base.Preconditions;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* A counter which records bunch of statistics for frequently occuring
* operations. Calculates: count, total time, average time, maximum time
* & slow operations.
*/
public class PerfCounter {
private static class OperationStats {
private long count = 0;
private boolean isCounter = false;
private long maxTimeNanos = 0;
private long slowCount = 0;
private long totalSlowTimeNanos = 0;
private long totalTimeNanos = 0;
@Override
public String toString() {
StringBuilder result = new StringBuilder();
if (!isCounter) {
result.append(count);
result.append("/");
result.append(totalTimeNanos / 1000000000.0);
result.append("/");
result.append(totalTimeNanos / 1000000000.0 / count);
result.append("/");
result.append(maxTimeNanos / 1000000000.0);
result.append("/");
result.append(slowCount);
result.append("/");
result.append(totalSlowTimeNanos * 1.0 / totalTimeNanos);
result.append(" ");
result.append(
"(count/total_time/avg_time/max_time/slow_count/slow_ratio)");
} else {
result.append(count);
result.append(" (count)");
}
return result.toString();
}
}
/**
* Flag for enabling performance logging.
*/
private static boolean enabled =
Boolean.parseBoolean(System.getProperty("gwt.perfcounters"));
private static final ThreadLocal> operationsStartTime =
new ThreadLocal>() {
@Override
protected Map initialValue() {
return new HashMap();
}
};
private static final Map operationStats =
new HashMap();
/**
* Record the end of the operation.
*/
public static void end(String operation, long slowThresholdNano) {
if (!enabled) {
return;
}
long finishTime = System.nanoTime();
Map startTimes = operationsStartTime.get();
Long startTime;
synchronized (startTimes) {
startTime = startTimes.remove(operation);
}
Preconditions.checkNotNull(startTime);
synchronized (operationStats) {
OperationStats stats = getStats(operation);
stats.count++;
long elapsedTime = finishTime - startTime.longValue();
stats.totalTimeNanos += elapsedTime;
stats.maxTimeNanos = Math.max(stats.maxTimeNanos, elapsedTime);
if (elapsedTime > slowThresholdNano) {
stats.slowCount++;
stats.totalSlowTimeNanos += elapsedTime;
}
}
}
/**
* Increment counter.
*/
public static void inc(String operation) {
synchronized (operationStats) {
OperationStats stats = getStats(operation);
stats.count++;
stats.isCounter = true;
}
}
public static void print() {
if (!enabled) {
return;
}
System.out.println("------------- Perf Counters -------------");
synchronized (operationStats) {
List keys = new ArrayList(operationStats.keySet());
Collections.sort(keys);
for (String operation : keys) {
System.out.println(operation + ": " + operationStats.get(operation));
}
}
System.out.println("-----------------------------------------");
}
/**
* Start operation.
*/
public static void start(String operation) {
if (!enabled) {
return;
}
Map startTimes = operationsStartTime.get();
synchronized (startTimes) {
Preconditions.checkState(!startTimes.containsKey(operation));
long startTime = System.nanoTime();
startTimes.put(operation, new Long(startTime));
}
}
private static OperationStats getStats(String operation) {
OperationStats stats = operationStats.get(operation);
if (stats == null) {
stats = new OperationStats();
operationStats.put(operation, stats);
}
return stats;
}
}