ecab306338
* Remove commented-out params from the script * General cleanup and refactoring * Deoptimize parseTemperatureSimple * Optimize nameEquals()
560 lines
22 KiB
Java
560 lines
22 KiB
Java
/*
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* Copyright 2023 The original authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package dev.morling.onebrc;
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import sun.misc.Unsafe;
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import java.io.File;
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import java.io.RandomAccessFile;
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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.reflect.Field;
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import java.nio.ByteBuffer;
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import java.nio.ByteOrder;
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import java.nio.channels.FileChannel.MapMode;
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import java.nio.charset.StandardCharsets;
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import java.util.ArrayList;
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import java.util.Arrays;
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public class CalculateAverage_mtopolnik {
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private static final Unsafe UNSAFE = unsafe();
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private static final int MAX_NAME_LEN = 100;
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private static final int STATS_TABLE_SIZE = 1 << 16;
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private static final int TABLE_INDEX_MASK = STATS_TABLE_SIZE - 1;
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private static final String MEASUREMENTS_TXT = "measurements.txt";
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private static final byte SEMICOLON = ';';
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private static final long BROADCAST_SEMICOLON = broadcastByte(SEMICOLON);
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// These two are just informative, I let the IDE calculate them for me
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private static final long NATIVE_MEM_PER_THREAD = StatsAccessor.SIZEOF * STATS_TABLE_SIZE;
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private static final long NATIVE_MEM_ON_8_THREADS = 8 * NATIVE_MEM_PER_THREAD;
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private static Unsafe unsafe() {
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try {
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Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
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theUnsafe.setAccessible(true);
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return (Unsafe) theUnsafe.get(Unsafe.class);
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}
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catch (NoSuchFieldException | IllegalAccessException e) {
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throw new RuntimeException(e);
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}
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}
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static class StationStats implements Comparable<StationStats> {
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String name;
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long sum;
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int count;
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int min;
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int max;
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@Override
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public String toString() {
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return String.format("%s=%.1f/%.1f/%.1f", name, min / 10.0, Math.round((double) sum / count) / 10.0, max / 10.0);
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}
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@Override
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public boolean equals(Object that) {
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return that.getClass() == StationStats.class && ((StationStats) that).name.equals(this.name);
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}
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@Override
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public int compareTo(StationStats that) {
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return name.compareTo(that.name);
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}
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}
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public static void main(String[] args) throws Exception {
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calculate();
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}
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static void calculate() throws Exception {
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final File file = new File(MEASUREMENTS_TXT);
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final long length = file.length();
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final int chunkCount = Runtime.getRuntime().availableProcessors();
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final var results = new StationStats[chunkCount][];
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final var chunkStartOffsets = new long[chunkCount];
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try (var raf = new RandomAccessFile(file, "r")) {
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final var inputBase = raf.getChannel().map(MapMode.READ_ONLY, 0, length, Arena.global()).address();
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for (int i = 1; i < chunkStartOffsets.length; i++) {
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var start = length * i / chunkStartOffsets.length;
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raf.seek(start);
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while (raf.read() != (byte) '\n') {
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}
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start = raf.getFilePointer();
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chunkStartOffsets[i] = start;
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}
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var threads = new Thread[chunkCount];
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for (int i = 0; i < chunkCount; i++) {
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final long chunkStart = chunkStartOffsets[i];
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final long chunkLimit = (i + 1 < chunkCount) ? chunkStartOffsets[i + 1] : length;
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threads[i] = new Thread(new ChunkProcessor(inputBase + chunkStart, inputBase + chunkLimit, results, i));
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}
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for (var thread : threads) {
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thread.start();
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}
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for (var thread : threads) {
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thread.join();
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}
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}
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mergeSortAndPrint(results);
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}
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private static class ChunkProcessor implements Runnable {
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private static final long NAMEBUF_SIZE = 2 * Long.BYTES;
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private static final int CACHELINE_SIZE = 64;
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private final long inputBase;
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private final long inputSize;
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private final StationStats[][] results;
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private final int myIndex;
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private StatsAccessor stats;
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private long nameBufBase;
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private long cursor;
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ChunkProcessor(long chunkStart, long chunkLimit, StationStats[][] results, int myIndex) {
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this.inputBase = chunkStart;
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this.inputSize = chunkLimit - chunkStart;
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this.results = results;
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this.myIndex = myIndex;
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}
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@Override
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public void run() {
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try (Arena confinedArena = Arena.ofConfined()) {
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long totalAllocated = 0;
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String threadName = Thread.currentThread().getName();
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long statsByteSize = STATS_TABLE_SIZE * StatsAccessor.SIZEOF;
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var diagnosticString = String.format("Thread %s needs %,d bytes, managed to allocate before OOM: ",
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threadName, statsByteSize + NAMEBUF_SIZE);
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try {
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stats = new StatsAccessor(confinedArena.allocate(statsByteSize, CACHELINE_SIZE));
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totalAllocated = statsByteSize;
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nameBufBase = confinedArena.allocate(NAMEBUF_SIZE).address();
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}
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catch (OutOfMemoryError e) {
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System.err.print(diagnosticString);
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System.err.println(totalAllocated);
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throw e;
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}
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processChunk();
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exportResults();
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}
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}
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private static final int MAX_TEMPERATURE_LEN = 5;
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private static final int MAX_ROW_LEN = MAX_NAME_LEN + 1 + MAX_TEMPERATURE_LEN + 1;
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private static final long DANGER_ZONE_LENGTH = ((MAX_ROW_LEN - 1) / 8 * 8 + 8);
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private void processChunk() {
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while (cursor < inputSize) {
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boolean withinSafeZone;
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long word1;
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long word2;
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long nameLen;
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long nameStartAddress = inputBase + cursor;
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if (cursor + DANGER_ZONE_LENGTH <= inputSize) {
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withinSafeZone = true;
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word1 = UNSAFE.getLong(nameStartAddress);
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word2 = UNSAFE.getLong(nameStartAddress + Long.BYTES);
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nameLen = nameLen(word1, word2, withinSafeZone);
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word1 = maskWord(word1, nameLen);
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word2 = maskWord(word2, nameLen - Long.BYTES);
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}
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else {
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withinSafeZone = false;
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UNSAFE.putLong(nameBufBase, 0);
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UNSAFE.putLong(nameBufBase + Long.BYTES, 0);
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UNSAFE.copyMemory(nameStartAddress, nameBufBase, Long.min(NAMEBUF_SIZE, inputSize - cursor));
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word1 = UNSAFE.getLong(nameBufBase);
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word2 = UNSAFE.getLong(nameBufBase + Long.BYTES);
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nameLen = nameLen(word1, word2, withinSafeZone);
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}
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long hash = hash(word1);
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assert nameLen > 0 && nameLen <= 100 : nameLen;
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long tempStartAddress = nameStartAddress + nameLen + 1;
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int temperature = withinSafeZone
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? parseTemperatureSwarAndAdvanceCursor(tempStartAddress)
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: parseTemperatureSimpleAndAdvanceCursor(tempStartAddress);
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updateStats(hash, nameStartAddress, nameLen, word1, word2, temperature, withinSafeZone);
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}
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}
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private void updateStats(
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long hash, long nameStartAddress, long nameLen, long nameWord1, long nameWord2,
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int temperature, boolean withinSafeZone) {
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int tableIndex = (int) (hash & TABLE_INDEX_MASK);
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while (true) {
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stats.gotoIndex(tableIndex);
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if (stats.hash() == hash && stats.nameLen() == nameLen && nameEquals(
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stats.nameAddress(), nameStartAddress, nameLen, nameWord1, nameWord2, withinSafeZone)) {
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stats.setSum(stats.sum() + temperature);
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stats.setCount(stats.count() + 1);
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stats.setMin((short) Integer.min(stats.min(), temperature));
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stats.setMax((short) Integer.max(stats.max(), temperature));
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return;
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}
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if (stats.nameLen() != 0) {
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tableIndex = (tableIndex + 1) & TABLE_INDEX_MASK;
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continue;
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}
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stats.setHash(hash);
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stats.setNameLen((int) nameLen);
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stats.setSum(temperature);
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stats.setCount(1);
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stats.setMin((short) temperature);
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stats.setMax((short) temperature);
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UNSAFE.copyMemory(nameStartAddress, stats.nameAddress(), nameLen);
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return;
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}
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}
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// Credit: merykitty
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private int parseTemperatureSwarAndAdvanceCursor(long tempStartAddress) {
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long word = UNSAFE.getLong(tempStartAddress);
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final long negated = ~word;
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final int dotPos = Long.numberOfTrailingZeros(negated & 0x10101000);
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cursor = (tempStartAddress + (dotPos / 8) + 3) - inputBase;
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final long signed = (negated << 59) >> 63;
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final long removeSignMask = ~(signed & 0xFF);
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final long digits = ((word & removeSignMask) << (28 - dotPos)) & 0x0F000F0F00L;
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final long absValue = ((digits * 0x640a0001) >>> 32) & 0x3FF;
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return (int) ((absValue ^ signed) - signed);
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}
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private int parseTemperatureSimpleAndAdvanceCursor(long tempStartAddress) {
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final byte minus = (byte) '-';
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final byte zero = (byte) '0';
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final byte dot = (byte) '.';
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byte ch = UNSAFE.getByte(tempStartAddress);
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long address = tempStartAddress;
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int temperature;
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int sign;
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if (ch == minus) {
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sign = -1;
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address++;
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ch = UNSAFE.getByte(address);
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}
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else {
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sign = 1;
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}
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temperature = ch - zero;
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address++;
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ch = UNSAFE.getByte(address);
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if (ch == dot) {
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address++;
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ch = UNSAFE.getByte(address);
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}
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else {
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temperature = 10 * temperature + (ch - zero);
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address += 2;
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ch = UNSAFE.getByte(address);
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}
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temperature = 10 * temperature + (ch - zero);
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// address - inputBase is the length of the temperature field.
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// A newline character follows the temperature, and so we advance
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// the cursor past the newline to the start of the next line.
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cursor = (address + 2) - inputBase;
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return sign * temperature;
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}
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private static long hash(long word1) {
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long seed = 0x51_7c_c1_b7_27_22_0a_95L;
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int rotDist = 17;
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long hash = word1;
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hash *= seed;
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hash = Long.rotateLeft(hash, rotDist);
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// hash ^= word2;
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// hash *= seed;
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// hash = Long.rotateLeft(hash, rotDist);
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return hash;
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}
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private static boolean nameEquals(long statsAddr, long inputAddr, long len, long inputWord1, long inputWord2,
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boolean withinSafeZone) {
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boolean mismatch1 = maskWord(inputWord1, len) != UNSAFE.getLong(statsAddr);
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boolean mismatch2 = maskWord(inputWord2, len - Long.BYTES) != UNSAFE.getLong(statsAddr + Long.BYTES);
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if (len <= 2 * Long.BYTES) {
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return !(mismatch1 | mismatch2);
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}
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if (withinSafeZone) {
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int i = 2 * Long.BYTES;
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for (; i <= len - Long.BYTES; i += Long.BYTES) {
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if (UNSAFE.getLong(inputAddr + i) != UNSAFE.getLong(statsAddr + i)) {
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return false;
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}
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}
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return maskWord(UNSAFE.getLong(inputAddr + i), len - i) == UNSAFE.getLong(statsAddr + i);
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}
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else {
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for (int i = 2 * Long.BYTES; i < len; i++) {
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if (UNSAFE.getByte(inputAddr + i) != UNSAFE.getByte(statsAddr + i)) {
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return false;
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}
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}
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}
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return true;
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}
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private static long maskWord(long word, long len) {
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long halfShiftDistance = Long.max(0, Long.BYTES - len) << 2;
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long mask = (~0L >>> halfShiftDistance) >>> halfShiftDistance; // avoid Java trap of shiftDist % 64
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return word & mask;
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}
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private static final long BROADCAST_0x01 = broadcastByte(0x01);
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private static final long BROADCAST_0x80 = broadcastByte(0x80);
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// Adapted from https://jameshfisher.com/2017/01/24/bitwise-check-for-zero-byte/
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// and https://github.com/ashvardanian/StringZilla/blob/14e7a78edcc16b031c06b375aac1f66d8f19d45a/stringzilla/stringzilla.h#L139-L169
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long nameLen(long word1, long word2, boolean withinSafeZone) {
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{
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long matchBits1 = matchBits(word1);
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long matchBits2 = matchBits(word2);
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if ((matchBits1 | matchBits2) != 0) {
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int trailing1 = Long.numberOfTrailingZeros(matchBits1);
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int match1IsNonZero = trailing1 & 63;
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match1IsNonZero |= match1IsNonZero >>> 3;
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match1IsNonZero |= match1IsNonZero >>> 1;
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match1IsNonZero |= match1IsNonZero >>> 1;
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// Now match1IsNonZero is 1 if it's non-zero, else 0. Use it to
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// raise the lowest bit in trailing2 if trailing1 is nonzero. This forces
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// trailing2 to be zero if trailing1 is non-zero.
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int trailing2 = Long.numberOfTrailingZeros(matchBits2 | match1IsNonZero) & 63;
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// trailing1 | trailing2 works like trailing1 + trailing2 because if trailing2 is non-zero,
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// then trailing1 is 64, and since trailing2 is < 64, there's no bit overlap.
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return (trailing1 | trailing2) >> 3;
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}
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}
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long nameStartAddress = inputBase + cursor;
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long address = nameStartAddress + 2 * Long.BYTES;
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long limit = inputBase + inputSize;
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if (withinSafeZone) {
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for (; address < limit; address += Long.BYTES) {
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var block = maskWord(UNSAFE.getLong(address), limit - address);
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long matchBits = matchBits(block);
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if (matchBits != 0) {
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return address + (Long.numberOfTrailingZeros(matchBits) >> 3) - nameStartAddress;
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}
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}
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throw new RuntimeException("Semicolon not found");
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}
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return addrOfSemicolonSafe(address, limit) - nameStartAddress;
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}
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private static long addrOfSemicolonSafe(long address, long limit) {
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for (; address < limit - Long.BYTES + 1; address += Long.BYTES) {
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var block = UNSAFE.getLong(address);
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long matchBits = matchBits(block);
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if (matchBits != 0) {
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return address + (Long.numberOfTrailingZeros(matchBits) >> 3);
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}
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}
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for (; address < limit; address++) {
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if (UNSAFE.getByte(address) == SEMICOLON) {
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return address;
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}
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}
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throw new RuntimeException("Semicolon not found");
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}
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private static long matchBits(long word) {
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long diff = word ^ BROADCAST_SEMICOLON;
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return (diff - BROADCAST_0x01) & ~diff & BROADCAST_0x80;
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}
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// Copies the results from native memory to Java heap and puts them into the results array.
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private void exportResults() {
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var exportedStats = new ArrayList<StationStats>(10_000);
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for (int i = 0; i < STATS_TABLE_SIZE; i++) {
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stats.gotoIndex(i);
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if (stats.nameLen() == 0) {
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continue;
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}
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var sum = stats.sum();
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var count = stats.count();
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var min = stats.min();
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var max = stats.max();
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var name = stats.exportNameString();
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var stationStats = new StationStats();
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stationStats.name = name;
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stationStats.sum = sum;
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stationStats.count = count;
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stationStats.min = min;
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stationStats.max = max;
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exportedStats.add(stationStats);
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}
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StationStats[] exported = exportedStats.toArray(new StationStats[0]);
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Arrays.sort(exported);
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results[myIndex] = exported;
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}
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private final ByteBuffer buf = ByteBuffer.allocate(8).order(ByteOrder.nativeOrder());
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private String longToString(long word) {
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buf.clear();
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buf.putLong(word);
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return new String(buf.array(), StandardCharsets.UTF_8); // + "|" + Arrays.toString(buf.array());
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}
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}
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private static long broadcastByte(int b) {
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long nnnnnnnn = b;
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nnnnnnnn |= nnnnnnnn << 8;
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nnnnnnnn |= nnnnnnnn << 16;
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nnnnnnnn |= nnnnnnnn << 32;
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return nnnnnnnn;
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}
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static class StatsAccessor {
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static final int NAME_SLOT_SIZE = 104;
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static final long HASH_OFFSET = 0;
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static final long NAMELEN_OFFSET = HASH_OFFSET + Long.BYTES;
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static final long SUM_OFFSET = NAMELEN_OFFSET + Integer.BYTES;
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static final long COUNT_OFFSET = SUM_OFFSET + Integer.BYTES;
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static final long MIN_OFFSET = COUNT_OFFSET + Integer.BYTES;
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static final long MAX_OFFSET = MIN_OFFSET + Short.BYTES;
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static final long NAME_OFFSET = MAX_OFFSET + Short.BYTES;
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static final long SIZEOF = (NAME_OFFSET + NAME_SLOT_SIZE - 1) / 8 * 8 + 8;
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static final int ARRAY_BASE_OFFSET = UNSAFE.arrayBaseOffset(byte[].class);
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private final long address;
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private long slotBase;
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StatsAccessor(MemorySegment memSeg) {
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memSeg.fill((byte) 0);
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this.address = memSeg.address();
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}
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void gotoIndex(int index) {
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slotBase = address + index * SIZEOF;
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}
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long hash() {
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return UNSAFE.getLong(slotBase + HASH_OFFSET);
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}
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int nameLen() {
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return UNSAFE.getInt(slotBase + NAMELEN_OFFSET);
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}
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int sum() {
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return UNSAFE.getInt(slotBase + SUM_OFFSET);
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}
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int count() {
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return UNSAFE.getInt(slotBase + COUNT_OFFSET);
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}
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short min() {
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return UNSAFE.getShort(slotBase + MIN_OFFSET);
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}
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short max() {
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return UNSAFE.getShort(slotBase + MAX_OFFSET);
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}
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long nameAddress() {
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return slotBase + NAME_OFFSET;
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}
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String exportNameString() {
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final var bytes = new byte[nameLen()];
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UNSAFE.copyMemory(null, nameAddress(), bytes, ARRAY_BASE_OFFSET, nameLen());
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return new String(bytes, StandardCharsets.UTF_8);
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}
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|
|
|
void setHash(long hash) {
|
|
UNSAFE.putLong(slotBase + HASH_OFFSET, hash);
|
|
}
|
|
|
|
void setNameLen(int nameLen) {
|
|
UNSAFE.putInt(slotBase + NAMELEN_OFFSET, nameLen);
|
|
}
|
|
|
|
void setSum(int sum) {
|
|
UNSAFE.putInt(slotBase + SUM_OFFSET, sum);
|
|
}
|
|
|
|
void setCount(int count) {
|
|
UNSAFE.putInt(slotBase + COUNT_OFFSET, count);
|
|
}
|
|
|
|
void setMin(short min) {
|
|
UNSAFE.putShort(slotBase + MIN_OFFSET, min);
|
|
}
|
|
|
|
void setMax(short max) {
|
|
UNSAFE.putShort(slotBase + MAX_OFFSET, max);
|
|
}
|
|
}
|
|
|
|
private static void mergeSortAndPrint(StationStats[][] results) {
|
|
var onFirst = true;
|
|
System.out.print('{');
|
|
var cursors = new int[results.length];
|
|
var indexOfMin = 0;
|
|
StationStats curr = null;
|
|
int exhaustedCount;
|
|
while (true) {
|
|
exhaustedCount = 0;
|
|
StationStats min = null;
|
|
for (int i = 0; i < cursors.length; i++) {
|
|
if (cursors[i] == results[i].length) {
|
|
exhaustedCount++;
|
|
continue;
|
|
}
|
|
StationStats candidate = results[i][cursors[i]];
|
|
if (min == null || min.compareTo(candidate) > 0) {
|
|
indexOfMin = i;
|
|
min = candidate;
|
|
}
|
|
}
|
|
if (exhaustedCount == cursors.length) {
|
|
if (!onFirst) {
|
|
System.out.print(", ");
|
|
}
|
|
System.out.print(curr);
|
|
break;
|
|
}
|
|
cursors[indexOfMin]++;
|
|
if (curr == null) {
|
|
curr = min;
|
|
}
|
|
else if (min.equals(curr)) {
|
|
curr.sum += min.sum;
|
|
curr.count += min.count;
|
|
curr.min = Integer.min(curr.min, min.min);
|
|
curr.max = Integer.max(curr.max, min.max);
|
|
}
|
|
else {
|
|
if (onFirst) {
|
|
onFirst = false;
|
|
}
|
|
else {
|
|
System.out.print(", ");
|
|
}
|
|
System.out.print(curr);
|
|
curr = min;
|
|
}
|
|
}
|
|
System.out.println('}');
|
|
}
|
|
}
|