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Add benchmark for strategies how to move a file

We can either
- try moving the file and, in case the target directory doesn't exist,
  handle the NoSuchFileException this raises to create the target
  directory
- or we always first test if the target directory exists and create it
 in case it is missing

On my Mac this yields

Benchmark                                        Mode  Cnt    Score     Error  Units
FileMoveBenchmark.moveFileToExistingDir        avgt    5  196.490 ±  15.194  us/op
FileMoveBenchmark.moveFileToExistingDirExists  avgt    5  223.217 ±  54.816  us/op
FileMoveBenchmark.moveFileToMissingDir         avgt    5  332.169 ±  43.871  us/op
FileMoveBenchmark.moveFileToMissingDirExists   avgt    5  303.815 ± 137.568  us/op

This means if the target directory of the move already exists the
first strategy is faster by around 25 us/op otherwise the second one
is faster by around 30 us/op. Which one is favorable depends on the
average probability that the target directory exists in real world
scenarios.

Change-Id: I03653b408b859a796508dfa1471b36c65633534e
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
master
Matthias Sohn 5 years ago
parent
commit
8a44216e8b
  1. 136
      org.eclipse.jgit.benchmarks/src/org/eclipse/jgit/benchmarks/FileMoveBenchmark.java

136
org.eclipse.jgit.benchmarks/src/org/eclipse/jgit/benchmarks/FileMoveBenchmark.java

@ -0,0 +1,136 @@
/*
* Copyright (C) 2020, Matthias Sohn <matthias.sohn@sap.com> and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.eclipse.jgit.benchmarks;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.util.concurrent.TimeUnit;
import org.eclipse.jgit.util.FileUtils;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.TearDown;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.RunnerException;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;
@State(Scope.Thread)
public class FileMoveBenchmark {
int i;
Path testDir;
Path targetDir;
@Setup
public void setupBenchmark() throws IOException {
testDir = Files.createTempDirectory("dir");
targetDir = testDir.resolve("target");
Files.createDirectory(targetDir);
}
@TearDown
public void teardown() throws IOException {
FileUtils.delete(testDir.toFile(),
FileUtils.RECURSIVE | FileUtils.RETRY);
}
@Benchmark
@BenchmarkMode({ Mode.AverageTime })
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@Warmup(iterations = 5, time = 1000, timeUnit = TimeUnit.MILLISECONDS)
@Measurement(iterations = 5, time = 5000, timeUnit = TimeUnit.MILLISECONDS)
public Path moveFileToExistingDir() throws IOException {
i++;
Path tmp = testDir.resolve("tmp" + i++);
Files.createFile(tmp);
Path targetDirectory = targetDir;
Path targetFile = targetDirectory.resolve("tmp" + i);
try {
return Files.move(tmp, targetFile, StandardCopyOption.ATOMIC_MOVE);
} catch (NoSuchFileException e) {
Files.createDirectory(targetDirectory);
return Files.move(tmp, targetFile, StandardCopyOption.ATOMIC_MOVE);
}
}
@Benchmark
@BenchmarkMode({ Mode.AverageTime })
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@Warmup(iterations = 5, time = 1000, timeUnit = TimeUnit.MILLISECONDS)
@Measurement(iterations = 5, time = 5000, timeUnit = TimeUnit.MILLISECONDS)
public Path moveFileToExistingDirExists() throws IOException {
Path tmp = testDir.resolve("tmp" + i++);
Files.createFile(tmp);
Path targetDirectory = targetDir;
Path targetFile = targetDir.resolve("tmp" + i);
if (!targetDirectory.toFile().exists()) {
Files.createDirectory(targetDirectory);
}
return Files.move(tmp, targetFile, StandardCopyOption.ATOMIC_MOVE);
}
@Benchmark
@BenchmarkMode({ Mode.AverageTime })
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@Warmup(iterations = 5, time = 1000, timeUnit = TimeUnit.MILLISECONDS)
@Measurement(iterations = 5, time = 5000, timeUnit = TimeUnit.MILLISECONDS)
public Path moveFileToMissingDir() throws IOException {
i++;
Path tmp = testDir.resolve("tmp" + i);
Files.createFile(tmp);
Path targetDirectory = testDir.resolve("target" + i);
Path targetFile = targetDirectory.resolve("tmp" + i);
try {
return Files.move(tmp, targetFile, StandardCopyOption.ATOMIC_MOVE);
} catch (NoSuchFileException e) {
Files.createDirectory(targetDirectory);
return Files.move(tmp, targetFile, StandardCopyOption.ATOMIC_MOVE);
}
}
@Benchmark
@BenchmarkMode({ Mode.AverageTime })
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@Warmup(iterations = 5, time = 1000, timeUnit = TimeUnit.MILLISECONDS)
@Measurement(iterations = 5, time = 5000, timeUnit = TimeUnit.MILLISECONDS)
public Path moveFileToMissingDirExists() throws IOException {
i++;
Path tmp = testDir.resolve("tmp" + i);
Files.createFile(tmp);
Path targetDirectory = testDir.resolve("target" + i);
Path targetFile = targetDirectory.resolve("tmp" + i);
if (!targetDirectory.toFile().exists()) {
Files.createDirectory(targetDirectory);
}
return Files.move(tmp, targetFile, StandardCopyOption.ATOMIC_MOVE);
}
public static void main(String[] args) throws RunnerException {
Options opt = new OptionsBuilder()
.include(FileMoveBenchmark.class
.getSimpleName())
// .addProfiler(StackProfiler.class)
// .addProfiler(GCProfiler.class)
.forks(1).jvmArgs("-ea").build();
new Runner(opt).run();
}
}
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