com.netflix.spectator.api.histogram.PercentileTimer Maven / Gradle / Ivy
/**
* Copyright 2015 Netflix, 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.netflix.spectator.api.histogram;
import com.netflix.spectator.api.Clock;
import com.netflix.spectator.api.Counter;
import com.netflix.spectator.api.Id;
import com.netflix.spectator.api.Measurement;
import com.netflix.spectator.api.Registry;
import com.netflix.spectator.api.Timer;
import java.util.Collections;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;
/**
* Timer that buckets the counts to allow for estimating percentiles.
*/
public final class PercentileTimer implements Timer {
/**
* Creates a timer object that can be used for estimating percentiles.
*
* @param registry
* Registry to use.
* @param id
* Identifier for the metric being registered.
* @return
* Timer that keeps track of counts by buckets that can be used to estimate
* the percentiles for the distribution.
*/
public static PercentileTimer get(Registry registry, Id id) {
return new PercentileTimer(registry, id);
}
private final Registry registry;
private final Id id;
private final Timer timer;
private final Counter[] counters;
/** Create a new instance. */
PercentileTimer(Registry registry, Id id) {
this.registry = registry;
this.id = id;
this.timer = registry.timer(id);
this.counters = new Counter[PercentileBuckets.length()];
for (int i = 0; i < counters.length; ++i) {
Id counterId = id.withTag("percentile", String.format("T%04X", i));
counters[i] = registry.counter(counterId);
}
}
@Override public Id id() {
return id;
}
@Override public Iterable measure() {
return Collections.emptyList();
}
@Override public boolean hasExpired() {
return timer.hasExpired();
}
@Override public void record(long amount, TimeUnit unit) {
final long nanos = unit.toNanos(amount);
timer.record(amount, unit);
counters[PercentileBuckets.indexOf(nanos)].increment();
}
@Override public T record(Callable rf) throws Exception {
final Clock clock = registry.clock();
final long s = clock.monotonicTime();
try {
return rf.call();
} finally {
final long e = clock.monotonicTime();
record(e - s, TimeUnit.NANOSECONDS);
}
}
@Override public void record(Runnable rf) {
final Clock clock = registry.clock();
final long s = clock.monotonicTime();
try {
rf.run();
} finally {
final long e = clock.monotonicTime();
record(e - s, TimeUnit.NANOSECONDS);
}
}
/**
* Computes the specified percentile for this timer. The unit will be seconds.
*
* @param p
* Percentile to compute, value must be {@code 0.0 <= p <= 100.0}.
* @return
* An approximation of the {@code p}`th percentile in seconds.
*/
public double percentile(double p) {
long[] counts = new long[PercentileBuckets.length()];
for (int i = 0; i < counts.length; ++i) {
counts[i] = counters[i].count();
}
double v = PercentileBuckets.percentile(counts, p);
return v / 1e9;
}
@Override public long count() {
return timer.count();
}
@Override public long totalTime() {
return timer.totalTime();
}
}