iaveryanov

<%@ page language="java" contentType="text/html;charset=UTF-8" %>
<%@ page import="org.apache.log4j.Level" %>
<%@ page import="org.apache.log4j.LogManager" %>
<%@ page import="org.apache.log4j.Logger" %>
<%@ page import="java.util.HashMap" %>
<%@ page import="java.util.Enumeration" %>
<%@ page import="java.util.Set" %>
<%@ page import="java.util.Arrays" %>
<% 
   /* This was originally suggested by Nelz on http://nelz.net/2008/04/08/log4j-runtime-configuration */

iaveryanov

Latency Comparison Numbers
--------------------------
L1 cache reference                            0.5 ns
Branch mispredict                             5   ns
L2 cache reference                            7   ns             14x L1 cache
Mutex lock/unlock                            25   ns
Main memory reference                       100   ns             20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy              3,000   ns
Send 1K bytes over 1 Gbps network        10,000   ns    0.01 ms
Read 4K randomly from SSD*              150,000   ns    0.15 ms

iaveryanov

public final class Utils {

	private Utils() {
	}
	
	public static void echo(String msg) {
		System.out.println(msg);
	}

	public static void sleep(int millis) {

iaveryanov

package ru.int_overflow;

import org.openjdk.jmh.annotations.*;
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;

import java.util.concurrent.TimeUnit;

iaveryanov

package ru.int_overflow;

public class IntOverflowPuzzle {

    // todo почему при использовании long разница в 1000 раз, действительно на столько медленнее
    // todo почему при переполнении разница во времени в 1000 раз
    private static void doOperation() {
        // change type to long
        //
        // results:

iaveryanov

package ru;

// origin source: http://arhipov.blogspot.ru/2014/02/java-8-lambdas-unintentional-puzzle.html
// my gist with puzzle https://gist.github.com/iaveryanov/10990181
public class Forrest {
    public Runnable wrooom(){
        return new Runnable() {
            @Override
            public void run() {
                System.out.println("Hello, lambda!");

iaveryanov

package lambda.puzzle;

// source: http://arhipov.blogspot.ru/2014/02/java-8-lambdas-unintentional-puzzle.html
public class Forrest {
    public Runnable wrooom(){
        return () -> { System.out.println("Hello, lambda!"); };
    }

    public static void main(String[] args) {
        Runnable runnable = new Forrest().wrooom();

iaveryanov

package ru;

public interface InterfaceJava8 {

    public static void main(String[] args) {
        System.out.println("Hello from interface! It is java 8!");
    }
}

iaveryanov

package ru.inlinetelecom.vn2.util;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;

/**
 * вариант с uncontended lock (getAvailableProcessors >= worker_count

iaveryanov

package ru.inlinetelecom.vn2.util;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;

/**
 * вариант с uncontended lock (getAvailableProcessors >= worker_count