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>
diff --git a/org.eclipse.jgit.benchmarks/src/org/eclipse/jgit/benchmarks/FileMoveBenchmark.java b/org.eclipse.jgit.benchmarks/src/org/eclipse/jgit/benchmarks/FileMoveBenchmark.java new file mode 100644 index 0000000..d3ada22 --- /dev/null +++ b/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(); + } +} \ No newline at end of file