8246338: Reduce overhead of normalizing file paths
Reviewed-by: alanb
This commit is contained in:
parent
ddbc7ed0a1
commit
0366f6bf45
src/java.base/unix/classes/java/io
test/micro/org/openjdk/bench/java/io
@ -1,5 +1,5 @@
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/*
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/*
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* Copyright (c) 1998, 2019, Oracle and/or its affiliates. All rights reserved.
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* Copyright (c) 1998, 2020, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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*
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* This code is free software; you can redistribute it and/or modify it
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* This code is free software; you can redistribute it and/or modify it
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@ -64,14 +64,17 @@ class UnixFileSystem extends FileSystem {
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/* A normal Unix pathname contains no duplicate slashes and does not end
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/* A normal Unix pathname contains no duplicate slashes and does not end
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with a slash. It may be the empty string. */
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with a slash. It may be the empty string. */
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/* Normalize the given pathname, whose length is len, starting at the given
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/**
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offset; everything before this offset is already normal. */
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* Normalize the given pathname, starting at the given
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private String normalize(String pathname, int len, int off) {
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* offset; everything before off is already normal, and there's at least
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if (len == 0) return pathname;
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* one duplicate or trailing slash to be removed
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int n = len;
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*/
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private String normalize(String pathname, int off) {
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int n = pathname.length();
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while ((n > 0) && (pathname.charAt(n - 1) == '/')) n--;
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while ((n > 0) && (pathname.charAt(n - 1) == '/')) n--;
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if (n == 0) return "/";
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if (n == 0) return "/";
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StringBuilder sb = new StringBuilder(pathname.length());
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StringBuilder sb = new StringBuilder(n);
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if (off > 0) sb.append(pathname, 0, off);
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if (off > 0) sb.append(pathname, 0, off);
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char prevChar = 0;
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char prevChar = 0;
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for (int i = off; i < n; i++) {
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for (int i = off; i < n; i++) {
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@ -88,22 +91,19 @@ class UnixFileSystem extends FileSystem {
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This way we iterate through the whole pathname string only once. */
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This way we iterate through the whole pathname string only once. */
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@Override
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@Override
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public String normalize(String pathname) {
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public String normalize(String pathname) {
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int n = pathname.length();
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int doubleSlash = pathname.indexOf("//");
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char prevChar = 0;
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if (doubleSlash >= 0) {
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for (int i = 0; i < n; i++) {
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return normalize(pathname, doubleSlash);
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char c = pathname.charAt(i);
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}
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if ((prevChar == '/') && (c == '/'))
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if (pathname.endsWith("/")) {
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return normalize(pathname, n, i - 1);
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return normalize(pathname, pathname.length() - 1);
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prevChar = c;
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}
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}
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if (prevChar == '/') return normalize(pathname, n, n - 1);
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return pathname;
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return pathname;
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}
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}
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@Override
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@Override
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public int prefixLength(String pathname) {
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public int prefixLength(String pathname) {
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if (pathname.isEmpty()) return 0;
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return pathname.startsWith("/") ? 1 : 0;
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return (pathname.charAt(0) == '/') ? 1 : 0;
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}
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}
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@Override
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@Override
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69
test/micro/org/openjdk/bench/java/io/FileOpen.java
Normal file
69
test/micro/org/openjdk/bench/java/io/FileOpen.java
Normal file
@ -0,0 +1,69 @@
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/*
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* Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package org.openjdk.bench.java.io;
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import org.openjdk.jmh.annotations.*;
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import org.openjdk.jmh.infra.Blackhole;
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import java.io.File;
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import java.util.concurrent.TimeUnit;
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/**
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* Tests the overheads of I/O API.
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*/
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@BenchmarkMode(Mode.AverageTime)
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@OutputTimeUnit(TimeUnit.MICROSECONDS)
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@State(Scope.Thread)
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@Warmup(time=2, iterations=5)
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@Measurement(time=3, iterations=5)
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@Fork(value=2, jvmArgs="-Xmx1g")
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public class FileOpen {
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public String normalFile = "/test/dir/file/name.txt";
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public String root = "/";
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public String trailingSlash = "/test/dir/file//name.txt";
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public String notNormalizedFile = "/test/dir/file//name.txt";
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@Benchmark
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public void mix(Blackhole bh) {
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bh.consume(new File(normalFile));
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bh.consume(new File(root));
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bh.consume(new File(trailingSlash));
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bh.consume(new File(notNormalizedFile));
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}
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@Benchmark
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public File normalized() {
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return new File(normalFile);
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}
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@Benchmark
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public File trailingSlash() {
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return new File(trailingSlash);
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}
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@Benchmark
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public File notNormalized() {
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return new File(notNormalizedFile);
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}
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}
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