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

/*
 * Copyright 2018 Andrei Pangin
 *
 * This is a specialized Java port of the FlameGraph script available at
 * https://github.com/brendangregg/FlameGraph/blob/master/flamegraph.pl
 *
 * Copyright 2016 Netflix, Inc.
 * Copyright 2011 Joyent, Inc.  All rights reserved.
 * Copyright 2011 Brendan Gregg.  All rights reserved.
 *

apangin

// Compile:
//     gcc -shared -fPIC -olibsighandle.so sighandle.c
//
// Run:
//     java -agentpath:/path/to/libsighandle.so ...
//     kill -37 <pid>

#include <signal.h>
#include <stdlib.h>
#include <unistd.h>

apangin

package bench;

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

import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.ThreadLocalRandom;

apangin

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

static jvmtiIterationControl JNICALL
heap_callback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data) {
    *tag_ptr = 1;
    return JVMTI_ITERATION_CONTINUE;
}

JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM* vm, char* options, void* reserved) {

apangin

package map;

import java.io.PrintStream;
import java.util.Base64;
import java.util.concurrent.ThreadLocalRandom;

public class MapGenerator {

    public static void main(String[] args) throws Exception {
        try (PrintStream out = new PrintStream("in.txt")) {

apangin

// Compile: gcc -O2 -fPIC -shared -o libproccount.so proccount.c
// Run:     LD_PRELOAD=/path/to/libproccount.so java args

#define _GNU_SOURCE
#include <sched.h>
#include <unistd.h>

static int online_cpus;

__attribute__((constructor))

apangin

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

#define INSIDE_MAIN 0x10000000
static volatile int max_depth = INSIDE_MAIN;

static intptr_t get_current_stack_depth(jvmtiEnv *jvmti) {
    intptr_t depth = 0;

apangin

Time	Shenandoah	CMS
0:00	2457603	5213181
0:05	2267273	57975399
0:10	2352205	4507923
0:15	2528657	4868730
0:20	2251922	4356681
0:25	2270476	50325870
0:30	2205635	4559177
0:35	2529011	73313110
0:40	2199077	4155792

apangin

#include <sched.h>
#include <stdio.h>
#include <time.h>

static long nanotime() {
    struct timespec tp;
    clock_gettime(CLOCK_MONOTONIC, &tp);
    return tp.tv_sec * 1000000000L + tp.tv_nsec;
}