8294432: Add provisions to calculate hash values from MemorySegments
Reviewed-by: mcimadamore
This commit is contained in:
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4a22c1fefc
commit
a1473ec302
@ -28,7 +28,9 @@ package jdk.internal.foreign;
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import jdk.internal.misc.ScopedMemoryAccess;
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import jdk.internal.util.Architecture;
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import jdk.internal.util.ArraysSupport;
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import jdk.internal.util.ByteArrayLittleEndian;
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import jdk.internal.vm.annotation.ForceInline;
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import jdk.internal.vm.annotation.Stable;
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import java.lang.foreign.MemorySegment;
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@ -156,6 +158,94 @@ public final class SegmentBulkOperations {
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}
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}
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private static final @Stable int[] POWERS_OF_31 = new int[]{
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0x0000001f, 0x000003c1, 0x0000745f, 0x000e1781,
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0x01b4d89f, 0x34e63b41, 0x67e12cdf, 0x94446f01};
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/**
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* {@return a 32-bit hash value calculated from the content in the provided
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* {@code segment} between the provided offsets}
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* <p>
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* The method is implemented as a 32-bit polynomial hash function equivalent to:
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* {@snippet lang=java :
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* final long length = toOffset - fromOffset;
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* segment.checkBounds(fromOffset, length);
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* int result = 1;
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* for (long i = fromOffset; i < toOffset; i++) {
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* result = 31 * result + segment.get(JAVA_BYTE, i);
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* }
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* return result;
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* }
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* but is potentially more performant.
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*
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* @param segment from which a content hash should be computed
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* @param fromOffset starting offset (inclusive) in the segment
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* @param toOffset ending offset (non-inclusive) in the segment
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* @throws WrongThreadException if this method is called from a thread {@code T},
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* such that {@code srcSegment.isAccessibleBy(T) == false}
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* @throws IllegalStateException if the {@linkplain MemorySegment#scope() scope}
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* associated with {@code segment} is not
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* {@linkplain MemorySegment.Scope#isAlive() alive}
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* @throws IndexOutOfBoundsException if either {@code fromOffset} or {@code toOffset}
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* are {@code > segment.byteSize}
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* @throws IndexOutOfBoundsException if either {@code fromOffset} or {@code toOffset}
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* are {@code < 0}
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* @throws IndexOutOfBoundsException if {@code toOffset - fromOffset} is {@code < 0}
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*/
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@ForceInline
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public static int contentHash(AbstractMemorySegmentImpl segment, long fromOffset, long toOffset) {
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final long length = toOffset - fromOffset;
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segment.checkBounds(fromOffset, length);
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if (length == 0) {
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// The state has to be checked explicitly for zero-length segments
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segment.scope.checkValidState();
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return 1;
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}
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int result = 1;
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final long longBytes = length & ((1L << 62) - 8);
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final long limit = fromOffset + longBytes;
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for (; fromOffset < limit; fromOffset += 8) {
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long val = SCOPED_MEMORY_ACCESS.getLongUnaligned(segment.sessionImpl(), segment.unsafeGetBase(), segment.unsafeGetOffset() + fromOffset, !Architecture.isLittleEndian());
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result = result * POWERS_OF_31[7]
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+ ((byte) (val >>> 56)) * POWERS_OF_31[6]
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+ ((byte) (val >>> 48)) * POWERS_OF_31[5]
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+ ((byte) (val >>> 40)) * POWERS_OF_31[4]
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+ ((byte) (val >>> 32)) * POWERS_OF_31[3]
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+ ((byte) (val >>> 24)) * POWERS_OF_31[2]
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+ ((byte) (val >>> 16)) * POWERS_OF_31[1]
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+ ((byte) (val >>> 8)) * POWERS_OF_31[0]
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+ ((byte) val);
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}
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int remaining = (int) (length - longBytes);
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// 0...0X00
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if (remaining >= 4) {
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int val = SCOPED_MEMORY_ACCESS.getIntUnaligned(segment.sessionImpl(), segment.unsafeGetBase(), segment.unsafeGetOffset() + fromOffset, !Architecture.isLittleEndian());
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result = result * POWERS_OF_31[3]
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+ ((byte) (val >>> 24)) * POWERS_OF_31[2]
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+ ((byte) (val >>> 16)) * POWERS_OF_31[1]
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+ ((byte) (val >>> 8)) * POWERS_OF_31[0]
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+ ((byte) val);
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fromOffset += 4;
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remaining -= 4;
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}
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// 0...00X0
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if (remaining >= 2) {
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short val = SCOPED_MEMORY_ACCESS.getShortUnaligned(segment.sessionImpl(), segment.unsafeGetBase(), segment.unsafeGetOffset() + fromOffset, !Architecture.isLittleEndian());
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result = result * POWERS_OF_31[1]
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+ ((byte) (val >>> 8)) * POWERS_OF_31[0]
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+ ((byte) val);
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fromOffset += 2;
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remaining -= 2;
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}
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// 0...000X
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if (remaining == 1) {
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byte val = SCOPED_MEMORY_ACCESS.getByte(segment.sessionImpl(), segment.unsafeGetBase(), segment.unsafeGetOffset() + fromOffset);
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result = result * POWERS_OF_31[0]
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+ val;
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}
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return result;
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}
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@ForceInline
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public static long mismatch(AbstractMemorySegmentImpl src, long srcFromOffset, long srcToOffset,
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AbstractMemorySegmentImpl dst, long dstFromOffset, long dstToOffset) {
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147
test/jdk/java/foreign/TestSegmentBulkOperationsContentHash.java
Normal file
147
test/jdk/java/foreign/TestSegmentBulkOperationsContentHash.java
Normal file
@ -0,0 +1,147 @@
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/*
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* Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* @test
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* @summary Test SegmentBulkOperations::contentHash
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* @modules java.base/jdk.internal.foreign
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* @run junit TestSegmentBulkOperationsContentHash
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*/
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import jdk.internal.foreign.AbstractMemorySegmentImpl;
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import jdk.internal.foreign.SegmentBulkOperations;
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import org.junit.jupiter.api.Disabled;
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import org.junit.jupiter.params.ParameterizedTest;
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import org.junit.jupiter.params.provider.Arguments;
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import org.junit.jupiter.params.provider.MethodSource;
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import java.lang.foreign.Arena;
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import java.lang.foreign.MemorySegment;
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import java.lang.foreign.ValueLayout;
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import java.util.Arrays;
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import java.util.concurrent.CompletableFuture;
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import java.util.concurrent.atomic.AtomicReference;
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import java.util.stream.IntStream;
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import java.util.stream.Stream;
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import static org.junit.jupiter.api.Assertions.*;
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final class TestSegmentBulkOperationsContentHash {
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@ParameterizedTest
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@MethodSource("sizes")
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@Disabled
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void testHashValues(int len) {
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try (var arena = Arena.ofConfined()) {
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for (int i = Byte.MIN_VALUE; i <= Byte.MAX_VALUE ; i++) {
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var segment = arena.allocate(len);
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segment.fill((byte) i);
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int hash = hash(segment);
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int expected = Arrays.hashCode(segment.toArray(ValueLayout.JAVA_BYTE));
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assertEquals(expected, hash, Arrays.toString(segment.toArray(ValueLayout.JAVA_BYTE)));
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}
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}
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}
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@ParameterizedTest
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@MethodSource("sizes")
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void testOffsets(int len) {
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if (len < 2) {
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return;
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}
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try (var arena = Arena.ofConfined()) {
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for (int i = Byte.MIN_VALUE; i <= Byte.MAX_VALUE ; i++) {
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var segment = arena.allocate(len);
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segment.fill((byte) i);
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int hash = hash(segment, 1, segment.byteSize() - 1);
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MemorySegment slice = segment.asSlice(1, segment.byteSize() - 2);
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byte[] arr = slice.toArray(ValueLayout.JAVA_BYTE);
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System.out.println(Arrays.toString(arr));
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int expected = Arrays.hashCode(arr);
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assertEquals(expected, hash, Arrays.toString(segment.toArray(ValueLayout.JAVA_BYTE)));
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}
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}
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}
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@ParameterizedTest
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@MethodSource("sizes")
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void testOutOfBounds(int len) {
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try (var arena = Arena.ofConfined()) {
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var segment = arena.allocate(len);
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assertThrows(IndexOutOfBoundsException.class,
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() -> hash(segment, 0, segment.byteSize() + 1));
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assertThrows(IndexOutOfBoundsException.class,
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() -> hash(segment, 0, -1));
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assertThrows(IndexOutOfBoundsException.class,
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() -> hash(segment, -1, 0));
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if (len > 2) {
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assertThrows(IndexOutOfBoundsException.class,
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() -> hash(segment, 2, 1));
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}
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}
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}
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@ParameterizedTest
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@MethodSource("sizes")
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void testConfinement(int len) {
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try (var arena = Arena.ofConfined()) {
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var segment = arena.allocate(len);
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AtomicReference<RuntimeException> ex = new AtomicReference<>();
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CompletableFuture<Void> future = CompletableFuture.runAsync(() -> {
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try {
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hash(segment);
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} catch (RuntimeException e) {
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ex.set(e);
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}
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});
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future.join();
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assertInstanceOf(WrongThreadException.class, ex.get());
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}
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}
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@ParameterizedTest
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@MethodSource("sizes")
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void testScope(int len) {
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var arena = Arena.ofConfined();
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var segment = arena.allocate(len);
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arena.close();
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assertThrows(IllegalStateException.class, () -> hash(segment));
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}
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private static int hash(MemorySegment segment) {
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return hash(segment, 0, segment.byteSize());
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}
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private static int hash(MemorySegment segment, long fromOffset, long toOffset) {
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return SegmentBulkOperations.contentHash((AbstractMemorySegmentImpl) segment, fromOffset, toOffset);
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}
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private static final int MAX_SIZE = 1 << 10;
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private static Stream<Arguments> sizes() {
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return IntStream.of(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 23, 32, 63, 128, 256, 511, MAX_SIZE)
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.boxed()
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.map(Arguments::of);
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}
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}
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@ -0,0 +1,101 @@
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/*
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* Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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package org.openjdk.bench.java.lang.foreign;
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import jdk.internal.foreign.AbstractMemorySegmentImpl;
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import jdk.internal.foreign.SegmentBulkOperations;
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import org.openjdk.jmh.annotations.Benchmark;
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import org.openjdk.jmh.annotations.BenchmarkMode;
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import org.openjdk.jmh.annotations.Fork;
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import org.openjdk.jmh.annotations.Measurement;
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import org.openjdk.jmh.annotations.Mode;
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import org.openjdk.jmh.annotations.OutputTimeUnit;
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import org.openjdk.jmh.annotations.Param;
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import org.openjdk.jmh.annotations.Scope;
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import org.openjdk.jmh.annotations.Setup;
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import org.openjdk.jmh.annotations.State;
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import org.openjdk.jmh.annotations.Warmup;
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import java.lang.foreign.Arena;
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import java.lang.foreign.MemorySegment;
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import java.util.Arrays;
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import java.util.Random;
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import java.util.concurrent.TimeUnit;
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import static java.lang.foreign.ValueLayout.JAVA_BYTE;
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@BenchmarkMode(Mode.AverageTime)
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@Warmup(iterations = 5, time = 500, timeUnit = TimeUnit.MILLISECONDS)
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@Measurement(iterations = 10, time = 500, timeUnit = TimeUnit.MILLISECONDS)
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@State(Scope.Thread)
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@OutputTimeUnit(TimeUnit.NANOSECONDS)
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@Fork(value = 3, jvmArgs = {"--add-exports=java.base/jdk.internal.foreign=ALL-UNNAMED"})
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public class SegmentBulkHash {
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@Param({"8", "64"})
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public int ELEM_SIZE;
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byte[] array;
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AbstractMemorySegmentImpl heapSegment;
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AbstractMemorySegmentImpl nativeSegment;
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@Setup
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public void setup() {
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// Always use the same alignment regardless of size
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nativeSegment = (AbstractMemorySegmentImpl) Arena.ofAuto().allocate(ELEM_SIZE, 16);
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var rnd = new Random(42);
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for (int i = 0; i < ELEM_SIZE; i++) {
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nativeSegment.set(JAVA_BYTE, i, (byte) rnd.nextInt(Byte.MIN_VALUE, Byte.MAX_VALUE));
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}
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array = nativeSegment.toArray(JAVA_BYTE);
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heapSegment = (AbstractMemorySegmentImpl) MemorySegment.ofArray(array);
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}
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@Benchmark
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public int array() {
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return Arrays.hashCode(array);
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}
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@Benchmark
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public int heapSegment() {
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return SegmentBulkOperations.contentHash(heapSegment, 0, ELEM_SIZE);
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}
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@Benchmark
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public int nativeSegment() {
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return SegmentBulkOperations.contentHash(nativeSegment, 0, ELEM_SIZE);
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}
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@Benchmark
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public int nativeSegmentJava() {
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int result = 1;
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for (long i = 0; i < ELEM_SIZE; i++) {
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result = 31 * result + nativeSegment.get(JAVA_BYTE, i);
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}
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return result;
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}
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}
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