// ============================== HOW TO RUN THIS TEST: ====================================
//
// single thread:
// java -jar log4j-perf/target/benchmarks.jar ".*SimpleDateFormat.*" -f 1 -wi 5 -i 5
//
// multiple threads (for example, 4 threads):
// java -jar log4j-perf/target/benchmarks.jar ".*SimpleDateFormat.*" -f 1 -wi 5 -i 5 -t 4 -si true
//
// Usage help:
// java -jar log4j-perf/target/benchmarks.jar -help
//
@State(Scope.Benchmark)
public class SimpleDateFormatBenchmark {
private final Date date = new Date();
private final SimpleDateFormat simpleDateFormat = new SimpleDateFormat("HH:mm:ss.SSS");
private final ThreadLocal<SimpleDateFormat> threadLocal =
new ThreadLocal<SimpleDateFormat>() {
@Override
protected SimpleDateFormat initialValue() {
return new SimpleDateFormat("HH:mm:ss.SSS");
}
};
private final ThreadLocal<Formatter> localFormat =
new ThreadLocal<Formatter>() {
@Override
protected Formatter initialValue() {
return new Formatter();
}
};
private final FastDateFormat fastFormat = FastDateFormat.getInstance("HH:mm:ss.SSS");
private class CurrentTime {
private final long timestamp;
private final String formatted;
public CurrentTime(final long timestamp) {
this.timestamp = timestamp;
this.formatted = fastFormat.format(timestamp);
}
}
private class Formatter {
private final SimpleDateFormat format = new SimpleDateFormat("HH:mm:ss.SSS");
private long timestamp;
private String formatted;
public Formatter() {
this.timestamp = 0;
}
public String format(final long timestamp) {
if (timestamp != this.timestamp) {
this.timestamp = timestamp;
formatted = format.format(timestamp);
}
return formatted;
}
}
private final long currentTimestamp = 0;
private String cachedTime = null;
private final AtomicReference<CurrentTime> currentTime =
new AtomicReference<>(new CurrentTime(System.currentTimeMillis()));
public static void main(final String[] args) {}
@Benchmark
@BenchmarkMode(Mode.SampleTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public void baseline() {}
@Benchmark
@BenchmarkMode(Mode.SampleTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public String synchronizedFormat() {
final long timestamp = System.currentTimeMillis();
synchronized (simpleDateFormat) {
if (timestamp != currentTimestamp) {
cachedTime = simpleDateFormat.format(date);
}
return cachedTime;
}
}
@Benchmark
@BenchmarkMode(Mode.SampleTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public String threadLocalFormat() {
final long timestamp = System.currentTimeMillis();
return threadLocal.get().format(timestamp);
}
@Benchmark
@BenchmarkMode(Mode.SampleTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public String cachedFormat() {
final long timestamp = System.currentTimeMillis();
return localFormat.get().format(timestamp);
}
@Benchmark
@BenchmarkMode(Mode.SampleTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public String fastFormat() {
return fastFormat.format(System.currentTimeMillis());
}
@Benchmark
@BenchmarkMode(Mode.SampleTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public String atomicFormat() {
final long timestamp = System.currentTimeMillis();
final CurrentTime current = currentTime.get();
if (timestamp != current.timestamp) {
final CurrentTime newTime = new CurrentTime(timestamp);
if (currentTime.compareAndSet(current, newTime)) {
return newTime.formatted;
} else {
return currentTime.get().formatted;
}
}
return current.formatted;
}
}
@Benchmark
@BenchmarkMode(Mode.SampleTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public String fastFormat() {
return fastFormat.format(System.currentTimeMillis());
}
