# HG changeset patch # User kzhaldyb # Date 1438959481 -10800 # Node ID a45fb54484ad86c5aaba976477f7d4fd53675ee4 # Parent 8af2c4220477643c3559f16e0d1dab1e5ce6cbd2 8132708: Add tests for Humongous objects allocation threshold Summary: Added the test which checks that Humongous objects allocation threshold works as expected Reviewed-by: tschatzl, dfazunen diff -r 8af2c4220477 -r a45fb54484ad test/gc/g1/humongousObjects/Helpers.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/test/gc/g1/humongousObjects/Helpers.java Fri Aug 07 17:58:01 2015 +0300 @@ -0,0 +1,58 @@ +/* + * Copyright (c) 2015, 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. + * + */ + +package gc.g1.humongousObjects; + +import sun.hotspot.WhiteBox; + +public class Helpers { + + // In case of 128 byte padding + private static final int MAX_PADDING_SIZE = 128; + + /** + * Detects amount of extra bytes required to allocate a byte array. + * Allocating a byte[n] array takes more then just n bytes in the heap. + * Extra bytes are required to store object reference and the length. + * This amount depends on bitness and other factors. + * + * @return byte[] memory overhead + */ + public static int detectByteArrayAllocationOverhead() { + + WhiteBox whiteBox = WhiteBox.getWhiteBox(); + + int zeroLengthByteArraySize = (int) whiteBox.getObjectSize(new byte[0]); + + // Since we do not know is there any padding in zeroLengthByteArraySize we cannot just take byte[0] size as overhead + for (int i = 1; i < MAX_PADDING_SIZE + 1; ++i) { + int realAllocationSize = (int) whiteBox.getObjectSize(new byte[i]); + if (realAllocationSize != zeroLengthByteArraySize) { + // It means we did not have any padding on previous step + return zeroLengthByteArraySize - (i - 1); + } + } + throw new Error("We cannot find byte[] memory overhead - should not reach here"); + } +} diff -r 8af2c4220477 -r a45fb54484ad test/gc/g1/humongousObjects/TestHumongousThreshold.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/test/gc/g1/humongousObjects/TestHumongousThreshold.java Fri Aug 07 17:58:01 2015 +0300 @@ -0,0 +1,165 @@ +/* + * Copyright (c) 2015, 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. + * + */ + +package gc.g1.humongousObjects; + +import jdk.test.lib.Asserts; +import sun.hotspot.WhiteBox; + +/** + * @test TestHumongousThreshold + * @summary Checks that objects larger than half a region are allocated as humongous + * @requires vm.gc=="G1" | vm.gc=="null" + * @library /testlibrary /../../test/lib + * @modules java.management + * @build sun.hotspot.WhiteBox + * gc.g1.humongousObjects.Helpers + * gc.g1.humongousObjects.TestHumongousThreshold + * @run driver ClassFileInstaller sun.hotspot.WhiteBox + * sun.hotspot.WhiteBox$WhiteBoxPermission + * + * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. + * -XX:G1HeapRegionSize=1M + * gc.g1.humongousObjects.TestHumongousThreshold + * + * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. + * -XX:G1HeapRegionSize=2M + * gc.g1.humongousObjects.TestHumongousThreshold + * + * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. + * -XX:G1HeapRegionSize=4M + * gc.g1.humongousObjects.TestHumongousThreshold + * + * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. + * -XX:G1HeapRegionSize=8M + * gc.g1.humongousObjects.TestHumongousThreshold + * + * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. + * -XX:G1HeapRegionSize=16M + * gc.g1.humongousObjects.TestHumongousThreshold + * + * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. + * -XX:G1HeapRegionSize=32M + * gc.g1.humongousObjects.TestHumongousThreshold + * + */ + +public class TestHumongousThreshold { + private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox(); + private static final int REGION_SIZE = WHITE_BOX.g1RegionSize(); + private static final int MAX_CONTINUOUS_SIZE_CHECK = 129; + private static final int NON_HUMONGOUS_DIVIDER = 10; + + /** + * The method allocates byte[] with specified size and checks that: + * 1. byte[] is allocated as we specified in expectedHumongous. + * 2. byte[] is allocated as humongous if its size is large than a half of region and non-humongous otherwise. + * It uses WB to obtain the size of created byte[]. Only objects larger than half of region are expected + * to be humongous. + * + * @param arraySize size of allocation + * @param expectedHumongous expected humongous/non-humongous allocation + * @return allocated byte array + */ + + private static byte[] allocateAndCheck(int arraySize, boolean expectedHumongous) { + byte[] storage = new byte[arraySize]; + long objectSize = WHITE_BOX.getObjectSize(storage); + boolean shouldBeHumongous = objectSize > (REGION_SIZE / 2); + + Asserts.assertEquals(expectedHumongous, shouldBeHumongous, "Despite we expected this object to be " + + (expectedHumongous ? "humongous" : "non-humongous") + " it appeared otherwise when we checked " + + "object size - likely test bug; Allocation size = " + arraySize + "; Object size = " + objectSize + + "; region size = " + REGION_SIZE); + + Asserts.assertEquals(WHITE_BOX.g1IsHumongous(storage), shouldBeHumongous, + "Object should be allocated as " + (shouldBeHumongous ? "humongous" + : "non-humongous") + " but it wasn't; Allocation size = " + arraySize + "; Object size = " + + objectSize + "; region size = " + REGION_SIZE); + return storage; + } + + public static void main(String[] args) { + int byteArrayMemoryOverhead = Helpers.detectByteArrayAllocationOverhead(); + + // Largest non-humongous byte[] + int maxByteArrayNonHumongousSize = (REGION_SIZE / 2) - byteArrayMemoryOverhead; + + // Increment for non-humongous testing + int nonHumongousStep = maxByteArrayNonHumongousSize / NON_HUMONGOUS_DIVIDER; + + // Maximum byte[] that takes one region + int maxByteArrayOneRegionSize = REGION_SIZE - byteArrayMemoryOverhead; + + // Sizes in regions + // i,e, 1.0f means one region, 1.5f means one and half region etc + float[] humongousFactors = {0.8f, 1.0f, 1.2f, 1.5f, 1.7f, 2.0f, 2.5f}; + + // Some diagnostic output + System.out.format("%s started%n", TestHumongousThreshold.class.getName()); + System.out.format("Actual G1 region size %d%n", REGION_SIZE); + System.out.format("byte[] memory overhead %d%n", byteArrayMemoryOverhead); + + // Non-humongous allocations + System.out.format("Doing non-humongous allocations%n"); + + // Testing allocations with byte[] with length from 0 to MAX_CONTINUOUS_SIZE_CHECK + System.out.format("Testing allocations with byte[] with length from 0 to %d%n", MAX_CONTINUOUS_SIZE_CHECK); + for (int i = 0; i < MAX_CONTINUOUS_SIZE_CHECK; ++i) { + allocateAndCheck(i, false); + } + + // Testing allocations with byte[] with length from 0 to nonHumongousStep * NON_HUMONGOUS_DIVIDER + System.out.format("Testing allocations with byte[] with length from 0 to %d with step %d%n", + nonHumongousStep * NON_HUMONGOUS_DIVIDER, nonHumongousStep); + for (int i = 0; i < NON_HUMONGOUS_DIVIDER; ++i) { + allocateAndCheck(i * nonHumongousStep, false); + } + + // Testing allocations with byte[] of maximum non-humongous length + System.out.format("Testing allocations with byte[] of maximum non-humongous length %d%n", + maxByteArrayNonHumongousSize); + allocateAndCheck(maxByteArrayNonHumongousSize, false); + + // Humongous allocations + System.out.format("Doing humongous allocations%n"); + // Testing with minimum humongous object + System.out.format("Testing with byte[] of minimum humongous object %d%n", maxByteArrayNonHumongousSize + 1); + allocateAndCheck(maxByteArrayNonHumongousSize + 1, true); + + // Testing allocations with byte[] with length from (maxByteArrayNonHumongousSize + 1) to + // (maxByteArrayNonHumongousSize + 1 + MAX_CONTINUOUS_SIZE_CHECK) + System.out.format("Testing allocations with byte[] with length from %d to %d%n", + maxByteArrayNonHumongousSize + 1, maxByteArrayNonHumongousSize + 1 + MAX_CONTINUOUS_SIZE_CHECK); + for (int i = 0; i < MAX_CONTINUOUS_SIZE_CHECK; ++i) { + allocateAndCheck(maxByteArrayNonHumongousSize + 1 + i, true); + } + + // Checking that large (more than a half of region size) objects are humongous + System.out.format("Checking that large (more than a half of region size) objects are humongous%n"); + for (float factor : humongousFactors) { + allocateAndCheck((int) (maxByteArrayOneRegionSize * factor), true); + } + } +}