apangin

package bench;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;

import java.util.HashMap;
import java.util.Map;

apangin

import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

// See https://twitter.com/tagir_valeev/status/1402089474805354499
public class StringBuilderHash {

apangin

import java.util.ArrayList;
import java.util.concurrent.locks.LockSupport;
import java.util.stream.StreamSupport;

public class ParallelStream {

    public static int[] process(Iterable<Integer> iterable) {
        return StreamSupport.stream(iterable.spliterator(), true)
                .mapToInt(i -> {
                    LockSupport.parkNanos(1_000_000);

apangin

import sun.misc.Unsafe;

import javax.management.ObjectName;
import java.io.IOException;
import java.lang.management.ManagementFactory;
import java.lang.reflect.Field;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.FileChannel;
import java.nio.charset.StandardCharsets;

apangin

import one.log.event.ILoggingEvent;
import one.log.event.OperationLogEvent;
import one.log.stat.StatCollector;
import one.log.stat.Statistics;
import one.nio.mgt.DiagnosticCommand;
import one.nio.os.BatchThread;

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.regex.Matcher;

apangin

#include <jvmti.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

JNIEXPORT jint JNICALL
Agent_OnAttach(JavaVM* vm, char* options, void* reserved) {
    if (options != NULL) {
        int* addr = (int*)strtol(options, NULL, 0);
        printf("vmoption [%p] = %d\n", addr, *addr); fflush(stdout);

apangin

// Replaces implementation of Unsafe.allocateMemory/freeMemory
// to avoid long time-to-safepoint pauses.
//
// Compile: gcc -O3 -fno-omit-frame-pointer -fPIC -shared -olibunmalloc.so unmalloc.c
//
// Usage:   java -agentpath:/path/to/libunmalloc.so ...

#include <jvmti.h>
#include <stdint.h>
#include <stdio.h>

apangin

import sun.jvm.hotspot.debugger.Address;
import sun.jvm.hotspot.runtime.VM;
import sun.jvm.hotspot.tools.Tool;

import java.io.IOException;
import java.io.RandomAccessFile;

/**
 * Changes -XX:MaxJavaStackTraceDepth flag to 1000000 in runtime
 * without restarting the JVM.

apangin

/*
 * Copyright 2020 Andrei Pangin
 *
 * 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
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software

apangin

package string;

import org.openjdk.jmh.annotations.*;

import java.util.Random;
import java.util.concurrent.TimeUnit;

@BenchmarkMode(Mode.AverageTime)
@Fork(1)
@State(Scope.Thread)