Mercurial > hg > truffle
view test/compiler/7177917/Test7177917.java @ 6611:7383557659bd
7185699: G1: Prediction model discrepancies
Summary: Correct the result value of G1CollectedHeap::pending_card_num(). Change the code that calculates the GC efficiency of a non-young heap region to use historical data from mixed GCs and the actual number of live bytes when predicting how long it would take to collect the region. Changes were also reviewed by Thomas Schatzl.
Reviewed-by: azeemj, brutisso
author | johnc |
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date | Tue, 21 Aug 2012 14:10:39 -0700 |
parents | d50605d9417e |
children |
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/* * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ /* * Micro-benchmark for Math.pow() and Math.exp() */ import java.util.*; public class Test7177917 { static double d; static Random r = new Random(0); static long m_pow(double[][] values) { double res = 0; long start = System.nanoTime(); for (int i = 0; i < values.length; i++) { res += Math.pow(values[i][0], values[i][1]); } long stop = System.nanoTime(); d = res; return (stop - start) / 1000; } static long m_exp(double[] values) { double res = 0; long start = System.nanoTime(); for (int i = 0; i < values.length; i++) { res += Math.exp(values[i]); } long stop = System.nanoTime(); d = res; return (stop - start) / 1000; } static double[][] pow_values(int nb) { double[][] res = new double[nb][2]; for (int i = 0; i < nb; i++) { double ylogx = (1 + (r.nextDouble() * 2045)) - 1023; // 2045 rather than 2046 as a safety margin double x = Math.abs(Double.longBitsToDouble(r.nextLong())); while (x != x) { x = Math.abs(Double.longBitsToDouble(r.nextLong())); } double logx = Math.log(x) / Math.log(2); double y = ylogx / logx; res[i][0] = x; res[i][1] = y; } return res; } static double[] exp_values(int nb) { double[] res = new double[nb]; for (int i = 0; i < nb; i++) { double ylogx = (1 + (r.nextDouble() * 2045)) - 1023; // 2045 rather than 2046 as a safety margin double x = Math.E; double logx = Math.log(x) / Math.log(2); double y = ylogx / logx; res[i] = y; } return res; } static public void main(String[] args) { { // warmup double[][] warmup_values = pow_values(10); m_pow(warmup_values); for (int i = 0; i < 20000; i++) { m_pow(warmup_values); } // test pow perf double[][] values = pow_values(1000000); System.out.println("==> POW " + m_pow(values)); // force uncommon trap double[][] nan_values = new double[1][2]; nan_values[0][0] = Double.NaN; nan_values[0][1] = Double.NaN; m_pow(nan_values); // force recompilation for (int i = 0; i < 20000; i++) { m_pow(warmup_values); } // test pow perf again System.out.println("==> POW " + m_pow(values)); } { // warmup double[] warmup_values = exp_values(10); m_exp(warmup_values); for (int i = 0; i < 20000; i++) { m_exp(warmup_values); } // test pow perf double[] values = exp_values(1000000); System.out.println("==> EXP " + m_exp(values)); // force uncommon trap double[] nan_values = new double[1]; nan_values[0] = Double.NaN; m_exp(nan_values); // force recompilation for (int i = 0; i < 20000; i++) { m_exp(warmup_values); } // test pow perf again System.out.println("==> EXP " + m_exp(values)); } } }