Initial commit

.gitattributes

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+* text eol=lf

.gitignore

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+.idea/
+out/
+*.iml
+*.ipr
+*.iws
+.settings/
+bin/
+build/
+.classpath
+.project
+.gradle

build.gradle

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+plugins{
+	id 'me.champeau.gradle.jmh' version '0.5.0'
+}
+
+apply plugin: 'java'
+
+repositories {
+	mavenCentral()
+}
+
+wrapper {
+	gradleVersion = '6.5'
+}

gradle/wrapper/gradle-wrapper.properties

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+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

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+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# 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
+#
+#      https://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.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"

gradlew.bat

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+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

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+rootProject.name = 'LockBenchmark'

src/jmh/java/com/github/maltalex/lockbenchmark/LockBenchmark.java

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+package com.github.maltalex.lockbenchmark;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import java.util.concurrent.locks.StampedLock;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Level;
+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.infra.Blackhole;
+
+@Measurement(iterations = 5)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@State(Scope.Benchmark)
+public class LockBenchmark {
+
+	public static interface Data {
+		void write(double plus);
+		double read();
+	}
+
+	static class StampedData implements Data {
+		private double x;
+		private final StampedLock sl = new StampedLock();
+
+		public StampedData(int x) {
+			this.x = x;
+		}
+
+		public void write(double plus) {
+			long stamp = sl.writeLock();
+			x += plus;
+			sl.unlockWrite(stamp);
+		}
+
+		public double read() {
+			long stamp = sl.tryOptimisticRead();
+			double a = x;
+			if (!sl.validate(stamp)) {
+				stamp = sl.readLock();
+				a = x;
+				sl.unlockRead(stamp);
+			}
+			return a;
+		}
+	}
+
+	static class ReadWriteData implements Data {
+		private double x;
+		private final ReentrantReadWriteLock rrwl = new ReentrantReadWriteLock();
+
+		public ReadWriteData(int x) {
+			this.x = x;
+		}
+
+		public void write(double plus) {
+			rrwl.writeLock().lock();
+			x += plus;
+			rrwl.writeLock().unlock();
+		}
+
+		public double read() {
+			rrwl.readLock().lock();
+			double a = x;
+			rrwl.readLock().unlock();
+			return a;
+		}
+	}
+
+	static class ReentrantData implements Data {
+		private double x;
+		private final ReentrantLock rl = new ReentrantLock();
+
+		public ReentrantData(int x) {
+			this.x = x;
+		}
+
+		public void write(double plus) {
+			rl.lock();
+			x += plus;
+			rl.unlock();
+		}
+
+		public double read() {
+			rl.lock();
+			double a = x;
+			rl.unlock();
+			return a;
+		}
+	}
+
+	static class SynchronizedData implements Data {
+		private double x;
+
+		public SynchronizedData(int x) {
+			this.x = x;
+		}
+
+		public void write(double plus) {
+			synchronized (this) {
+				x += plus;
+			}
+		}
+
+		public double read() {
+			double a;
+			synchronized (this) {
+				a = x;
+			}
+			return a;
+		}
+	}
+
+	static class SpinData implements Data {
+		private double x;
+		AtomicBoolean ab = new AtomicBoolean();
+
+		public SpinData(int x) {
+			this.x = x;
+		}
+
+		public void write(double plus) {
+			while (!ab.compareAndSet(false, true)) {
+				Thread.yield();
+			}
+			x += plus;
+			ab.set(false);
+		}
+
+		public double read() {
+			double a;
+			while (!ab.compareAndSet(false, true)) {
+				Thread.yield();
+			}
+			a = x;
+			ab.set(false);
+			return a;
+		}
+	}
+
+	StampedData stampedData;
+	ReentrantData reentrantData;
+	ReadWriteData readWriteData;
+	SynchronizedData synchronizedData;
+	SpinData spinData;
+	ExecutorService executor;
+
+	int iterations = 1000;
+	int precent10 = 3;
+	int percent20 = 2 * precent10;
+	int percent50 = 5 * precent10;
+	int percent80 = 8 * precent10;
+	int percent90 = 9 * precent10;
+	int percent100 = 10 * precent10;
+
+	@Setup(Level.Trial)
+	public void setUp() {
+		stampedData = new StampedData(1);
+		reentrantData = new ReentrantData(1);
+		readWriteData = new ReadWriteData(1);
+		synchronizedData = new SynchronizedData(1);
+		spinData = new SpinData(1);
+		executor = Executors.newFixedThreadPool(percent100);
+	}
+
+	@TearDown(Level.Trial)
+	public void tearDown() {
+		executor.shutdown();
+	}
+
+	public void benchmark(Blackhole hole, Data d, int readers, int writers, int iterations) {
+		CompletableFuture<?>[] futures = new CompletableFuture<?>[readers + writers];
+		for (int i = 0; i < readers; i++) {
+			futures[i] = CompletableFuture.runAsync(() -> {
+				for (int j = 0; j < iterations; j++) {
+					hole.consume(d.read());
+					Thread.yield();
+				}
+			}, executor);
+		}
+		for (int i = readers; i < readers + writers; i++) {
+			futures[i] = CompletableFuture.runAsync(() -> {
+				for (int j = 0; j < iterations; j++) {
+					d.write(j);
+					Thread.yield();
+				}
+			}, executor);
+		}
+		try {
+			CompletableFuture.allOf(futures).get();
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
+
+	@Benchmark
+	public void stamped_r100_w0(Blackhole hole) {
+		benchmark(hole, stampedData, percent100, 0, iterations);
+	}
+
+	@Benchmark
+	public void reentrant_r100_w0(Blackhole hole) {
+		benchmark(hole, reentrantData, percent100, 0, iterations);
+	}
+
+	@Benchmark
+	public void readwrite_r100_w0(Blackhole hole) {
+		benchmark(hole, readWriteData, percent100, 0, iterations);
+	}
+
+	@Benchmark
+	public void synchronized_r100_w0(Blackhole hole) {
+		benchmark(hole, synchronizedData, percent100, 0, iterations);
+	}
+
+	@Benchmark
+	public void spin_r100_w0(Blackhole hole) {
+		benchmark(hole, spinData, percent100, 0, iterations);
+	}
+
+	@Benchmark
+	public void stamped_r90_w10(Blackhole hole) {
+		benchmark(hole, stampedData, percent90, precent10, iterations);
+	}
+
+	@Benchmark
+	public void reentrant_r90_w10(Blackhole hole) {
+		benchmark(hole, reentrantData, percent90, precent10, iterations);
+	}
+
+	@Benchmark
+	public void readwrite_r90_w10(Blackhole hole) {
+		benchmark(hole, readWriteData, percent90, precent10, iterations);
+	}
+
+	@Benchmark
+	public void synchronized_r90_w10(Blackhole hole) {
+		benchmark(hole, synchronizedData, percent90, precent10, iterations);
+	}
+
+	@Benchmark
+	public void spin_r90_w10(Blackhole hole) {
+		benchmark(hole, spinData, percent90, precent10, iterations);
+	}
+
+	@Benchmark
+	public void stamped_r80_w20(Blackhole hole) {
+		benchmark(hole, stampedData, percent80, percent20, iterations);
+	}
+
+	@Benchmark
+	public void reentrant_r80_w20(Blackhole hole) {
+		benchmark(hole, reentrantData, percent80, percent20, iterations);
+	}
+
+	@Benchmark
+	public void readwrite_r80_w20(Blackhole hole) {
+		benchmark(hole, readWriteData, percent80, percent20, iterations);
+	}
+
+	@Benchmark
+	public void synchronized_r80_w20(Blackhole hole) {
+		benchmark(hole, synchronizedData, percent80, percent20, iterations);
+	}
+
+	@Benchmark
+	public void spin_r80_w20(Blackhole hole) {
+		benchmark(hole, spinData, percent80, percent20, iterations);
+	}
+
+	@Benchmark
+	public void stamped_r50_w50(Blackhole hole) {
+		benchmark(hole, stampedData, percent50, percent50, iterations);
+	}
+
+	@Benchmark
+	public void reentrant_r50_w50(Blackhole hole) {
+		benchmark(hole, reentrantData, percent50, percent50, iterations);
+	}
+
+	@Benchmark
+	public void readwrite_r50_w50(Blackhole hole) {
+		benchmark(hole, readWriteData, percent50, percent50, iterations);
+	}
+
+	@Benchmark
+	public void synchronized_r50_w50(Blackhole hole) {
+		benchmark(hole, synchronizedData, percent50, percent50, iterations);
+	}
+
+	@Benchmark
+	public void spin_r50_w50(Blackhole hole) {
+		benchmark(hole, spinData, percent50, percent50, iterations);
+	}
+
+	@Benchmark
+	public void stamped_r0_w100(Blackhole hole) {
+		benchmark(hole, stampedData, 0, percent100, iterations);
+	}
+
+	@Benchmark
+	public void reentrant_r0_w100(Blackhole hole) {
+		benchmark(hole, reentrantData, 0, percent100, iterations);
+	}
+
+	@Benchmark
+	public void readwrite_r0_w100(Blackhole hole) {
+		benchmark(hole, readWriteData, 0, percent100, iterations);
+	}
+
+	@Benchmark
+	public void synchronized_r0_w100(Blackhole hole) {
+		benchmark(hole, synchronizedData, 0, percent100, iterations);
+	}
+
+	@Benchmark
+	public void spin_r0_w100(Blackhole hole) {
+		benchmark(hole, spinData, 0, percent100, iterations);
+	}
+}