LoopHelpers.java revision 0
1043N/A/*
1043N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1043N/A *
5359N/A * This code is free software; you can redistribute it and/or modify it
1043N/A * under the terms of the GNU General Public License version 2 only, as
1043N/A * published by the Free Software Foundation.
1043N/A *
1043N/A * This code is distributed in the hope that it will be useful, but WITHOUT
1043N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1043N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1043N/A * version 2 for more details (a copy is included in the LICENSE file that
1043N/A * accompanied this code).
1043N/A *
1043N/A * You should have received a copy of the GNU General Public License version
1043N/A * 2 along with this work; if not, write to the Free Software Foundation,
1043N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1043N/A *
1043N/A * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1043N/A * CA 95054 USA or visit www.sun.com if you need additional information or
1043N/A * have any questions.
2362N/A */
2362N/A
2362N/A/*
1043N/A * This file is available under and governed by the GNU General Public
1043N/A * License version 2 only, as published by the Free Software Foundation.
1043N/A * However, the following notice accompanied the original version of this
1043N/A * file:
1043N/A *
1043N/A * Written by Doug Lea with assistance from members of JCP JSR-166
1043N/A * Expert Group and released to the public domain, as explained at
1043N/A * http://creativecommons.org/licenses/publicdomain
1043N/A */
1043N/A/**
1043N/A * Misc utilities in JSR166 performance tests
1043N/A */
1043N/A
1043N/Aimport java.util.concurrent.*;
1043N/Aimport java.util.concurrent.atomic.*;
1043N/A
1043N/Aclass LoopHelpers {
1043N/A
1043N/A // Some mindless computation to do between synchronizations...
1043N/A
1043N/A /**
1043N/A * generates 32 bit pseudo-random numbers.
1043N/A * Adapted from http://www.snippets.org
1043N/A */
1043N/A public static int compute1(int x) {
1043N/A int lo = 16807 * (x & 0xFFFF);
1043N/A int hi = 16807 * (x >>> 16);
1043N/A lo += (hi & 0x7FFF) << 16;
1043N/A if ((lo & 0x80000000) != 0) {
1043N/A lo &= 0x7fffffff;
1043N/A ++lo;
1043N/A }
1043N/A lo += hi >>> 15;
1043N/A if (lo == 0 || (lo & 0x80000000) != 0) {
1043N/A lo &= 0x7fffffff;
1043N/A ++lo;
1043N/A }
5359N/A return lo;
5359N/A }
5359N/A
5359N/A /**
4638N/A * Computes a linear congruential random number a random number
4638N/A * of times.
4638N/A */
4638N/A public static int compute2(int x) {
1043N/A int loops = (x >>> 4) & 7;
1043N/A while (loops-- > 0) {
1043N/A x = (x * 2147483647) % 16807;
1043N/A }
1043N/A return x;
1043N/A }
1043N/A
1043N/A /**
1043N/A * An actually useful random number generator, but unsynchronized.
1043N/A * Basically same as java.util.Random.
1043N/A */
1043N/A public static class SimpleRandom {
1043N/A private final static long multiplier = 0x5DEECE66DL;
1043N/A private final static long addend = 0xBL;
1043N/A private final static long mask = (1L << 48) - 1;
3119N/A static final AtomicLong seq = new AtomicLong(1);
3119N/A private long seed = System.nanoTime() + seq.getAndIncrement();
3119N/A
3119N/A public void setSeed(long s) {
3119N/A seed = s;
1043N/A }
1043N/A
1043N/A public int next() {
1043N/A long nextseed = (seed * multiplier + addend) & mask;
1043N/A seed = nextseed;
1043N/A return ((int)(nextseed >>> 17)) & 0x7FFFFFFF;
1043N/A }
1043N/A }
1043N/A
1043N/A public static class BarrierTimer implements Runnable {
1043N/A public volatile long startTime;
1043N/A public volatile long endTime;
1043N/A public void run() {
1043N/A long t = System.nanoTime();
1043N/A if (startTime == 0)
1043N/A startTime = t;
1043N/A else
1043N/A endTime = t;
1043N/A }
1043N/A public void clear() {
1043N/A startTime = 0;
1043N/A endTime = 0;
}
public long getTime() {
return endTime - startTime;
}
}
public static String rightJustify(long n) {
// There's probably a better way to do this...
String field = " ";
String num = Long.toString(n);
if (num.length() >= field.length())
return num;
StringBuffer b = new StringBuffer(field);
b.replace(b.length()-num.length(), b.length(), num);
return b.toString();
}
}