/**
* Logback: the reliable, generic, fast and flexible logging framework.
*
* Copyright (C) 1999-2006, QOS.ch
*
* This library is free software, you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License as published by the Free
* Software Foundation.
*/
package chapter4;
import org.slf4j.Logger;
import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.PatternLayout;
import ch.qos.logback.core.FileAppender;
import ch.qos.logback.core.layout.EchoLayout;
public class IO extends Thread {
static String msgLong = "ABCDEGHIJKLMNOPQRSTUVWXYZabcdeghijklmnopqrstuvwxyz1234567890";
static String msgShort = "Hello";
static boolean scarceCPU;
static int numThreads;
static long l;
static boolean longMessage;
long len;
boolean buffered;
boolean immediateFlush;
Logger logger;
LoggerContext context;
double throughput;
public IO(boolean _buffered, boolean _immediateFlush, long _len) {
this.len = _len;
this.buffered = _buffered;
this.immediateFlush = _immediateFlush;
context = new LoggerContext();
logger = context.getLogger("logger-" + getName());
// A FileAppender is created according to the buffering and
// immediate flush setting of this IO instance.
FileAppender fa = new FileAppender();
if (longMessage) {
PatternLayout pa = new PatternLayout();
pa.setPattern("%r %5p %c [%t] - %m%n");
fa.setLayout(pa);
} else {
fa.setLayout(new EchoLayout());
}
fa.setFile(getName() + ".log");
fa.setAppend(false);
fa.setImmediateFlush(immediateFlush);
fa.setBufferedIO(buffered);
fa.setContext(context);
fa.start();
}
public static void main(String[] argv) throws Exception {
if (argv.length != 4) {
usage("Wrong number of arguments.");
}
l = Integer.parseInt(argv[0]);
numThreads = Integer.parseInt(argv[1]);
scarceCPU = "true".equalsIgnoreCase(argv[2]);
longMessage = "long".equalsIgnoreCase(argv[3]);
// ----------------------------------------------------
// first test with unbuffered IO and immediate flushing
perfCase(false, true, l);
// ----------------------------------------------------
// Second test with unbuffered IO and no immediate flushing
perfCase(false, false, l);
// ----------------------------------------------------
// Third test with buffered IO and no immediate flushing
perfCase(true, false, l);
// There is no fourth test as buffered IO and immediate flushing
// do not make sense.
}
static void usage(String msg) {
System.err.println(msg);
System.err.println("Usage: java " + IO.class.getName() +
" runLength numThreads scarceCPU (short|long)\n" +
" runLength (integer) the number of logs to generate perthread\n" +
" numThreads (integer) the number of threads.\n" +
" scarceCPU (boolean) if true an additional CPU intensive thread is created\n" +
" (short|long) length of log messages.");
System.exit(1);
}
static void perfCase(boolean buffered, boolean immediateFlush, long len)
throws Exception {
IO[] threads = new IO[numThreads];
Counter counterThread = null;
if (scarceCPU) {
counterThread = new Counter();
counterThread.start();
}
// First create the threads
for (int i = 0; i < numThreads; i++) {
threads[i] = new IO(buffered, immediateFlush, len);
}
// then start them
for (int i = 0; i < numThreads; i++) {
threads[i].start();
}
// wait for them to stop, compute the average throughputs
double sum = 0;
for (int i = 0; i < numThreads; i++) {
threads[i].join();
sum += threads[i].throughput;
}
if (scarceCPU) {
// setting the interrupted field will cause counterThread to stop
counterThread.interrupted = true;
counterThread.join();
}
System.out.println("On average throughput of " + (sum / numThreads) +
" logs per millisecond.");
System.out.println("------------------------------------------------");
}
public void run() {
String msg = msgShort;
if (longMessage) {
msg = msgLong;
}
long before = System.currentTimeMillis();
for (int i = 0; i < len; i++) {
logger.debug(msg);
}
throughput = (len * 1.0) / (System.currentTimeMillis() - before);
System.out.println(getName() + ", buffered: " + buffered +
", immediateFlush: " + immediateFlush + ", throughput: " + throughput +
" logs per millisecond.");
}
}
class Counter extends Thread {
public boolean interrupted = false;
public double counter = 0;
public void run() {
long before = System.currentTimeMillis();
while (!interrupted) {
counter += 0.001;
}
double tput = (counter * 1.0) / (System.currentTimeMillis() - before);
System.out.println("Counter thread " + getName() +
" incremented counter by " + tput + " per millisecond.");
}
}