Add implementation for user unbounded (#394)
Implementation that uses the Vector API for the following - scan for separators - calculate hash - n-way lookup in hash table - parse digits e; fix queue size
This commit is contained in:
unbounded
GitHub
437
src/main/java/dev/morling/onebrc/CalculateAverage_unbounded.java
Normal file
437
src/main/java/dev/morling/onebrc/CalculateAverage_unbounded.java
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@@ -0,0 +1,437 @@
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/*
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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 jdk.incubator.vector.*;
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import java.io.IOException;
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import java.lang.foreign.Arena;
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import java.lang.foreign.MemorySegment;
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import java.nio.ByteOrder;
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import java.nio.channels.FileChannel;
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import java.nio.file.Files;
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import java.nio.file.Path;
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import java.nio.file.StandardOpenOption;
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import java.util.*;
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import java.util.concurrent.ArrayBlockingQueue;
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import java.util.function.Consumer;
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import java.util.stream.Collectors;
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import java.util.stream.IntStream;
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import static java.lang.foreign.ValueLayout.*;
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import static java.nio.ByteOrder.BIG_ENDIAN;
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public class CalculateAverage_unbounded {
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private static final Path FILE = Path.of("./measurements.txt");
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private static final int MAX_STATION_NAME_LEN = 100;
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private static final int MAX_UNIQUE_STATIONS = 10000;
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// this is *really* expensive
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private static final OfInt BIG_ENDIAN_INT = JAVA_INT_UNALIGNED.withOrder(BIG_ENDIAN);
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private static final VectorSpecies<Byte> LINE_SCAN_SPECIES = ByteVector.SPECIES_256;
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private static final int LINE_SCAN_LEN = LINE_SCAN_SPECIES.length();
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private static final VectorSpecies<Integer> NAME_HASH_SPECIES = IntVector.SPECIES_256;
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private static final VectorSpecies<Short> HASH_LOOKUP_SPECIES = ShortVector.SPECIES_256;
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private static final VectorSpecies<Long> ACCUMULATOR_SPECIES = LongVector.SPECIES_256;
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private static final int CHUNK_SIZE = 16 * 1024 * 1024;
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// Arbitrarily chosen primes
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private static final int[] HASH_PRIMES = { 661, 1663, 2293, 3581, 5449, 5953, 6311, 6841, 7573, 7669, 7703, 7789, 7901, 8887, 8581, 8831 };
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private static final byte[] PREFIX_MASK = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, };
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private static final int[] DIGIT_MULTIPLIERS = {
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0, 10, 1, 1,
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100, 10, 1, 1,
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0, -10, 1, -1,
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-100, -10, 1, -1,
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};
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private static final int[] DIGIT_MASK = {
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0x000fff0f,
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0x0f0fff0f,
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0x000fff0f,
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0x0f0fff0f,
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};
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private static final int[] DIGIT_FLIPS = { 0, 0, -1, -1 };
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record Segment(long start, int len) {
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}
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static class StationStat {
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long count;
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long totalTemp;
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int min;
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int max;
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StationStat(long count, long totalTemp, int min, int max) {
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this.count = count;
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this.totalTemp = totalTemp;
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this.min = min;
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this.max = max;
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}
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StationStat merge(StationStat other) {
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this.count += other.count;
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this.totalTemp += other.totalTemp;
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this.min = Math.min(this.min, other.min);
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this.max = Math.max(this.max, other.max);
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return this;
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}
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@Override
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public String toString() {
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return STR."\{min/10.0}/\{Math.round(1.0 * totalTemp / count)/10.0}/\{max/10.0}";
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}
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}
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public static void main(String[] args) throws IOException, InterruptedException {
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long fileSize = Files.size(FILE);
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int lastChunkSize = (int) Math.min(200, fileSize);
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int numSegments = (int) (fileSize / CHUNK_SIZE + 10);
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var segments = new ArrayBlockingQueue<Segment>((int) (fileSize / CHUNK_SIZE + 10));
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for (long i = 0; i < fileSize - lastChunkSize; i += CHUNK_SIZE) {
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segments.put(new Segment(i, (int) Math.min(CHUNK_SIZE, fileSize - i - lastChunkSize)));
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}
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int numThreads = Runtime.getRuntime().availableProcessors();
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var results = new ArrayBlockingQueue<Map<String, StationStat>>(numThreads);
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var toMerge = new ArrayList<Map<String, StationStat>>(numThreads + 1);
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try (var ch = FileChannel.open(FILE, StandardOpenOption.READ); var arena = Arena.ofConfined()) {
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var threads = IntStream.range(0, numThreads).mapToObj((ignored) -> new ProcessorThread(segments, ch, results::add)).toList();
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threads.forEach(Thread::start);
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// Process last piece without OOB
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int margin = lastChunkSize < fileSize ? 1 : 0;
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var mem = ch.map(FileChannel.MapMode.READ_ONLY, fileSize - lastChunkSize - margin, lastChunkSize + margin, arena);
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slowProcessChunk(mem, margin, lastChunkSize, toMerge::add);
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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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results.drainTo(toMerge);
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var merged = toMerge.stream().reduce((a, b) -> {
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b.forEach((k, v) -> a.merge(k, v, StationStat::merge));
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return a;
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}).get();
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printResult(merged);
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}
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// Simple implementation for the end - so we don't need to worry about reading past the end of the file
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private static void slowProcessChunk(MemorySegment mem, int startPos, int endPos, Consumer<Map<String, StationStat>> report) {
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int index = scanForStartPos(mem, startPos);
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byte[] nameBuf = new byte[MAX_STATION_NAME_LEN];
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while (index < endPos) {
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int nameLen = 0;
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while (mem.get(JAVA_BYTE, index) != ';') {
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nameBuf[nameLen++] = mem.get(JAVA_BYTE, index);
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index++;
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}
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var name = new String(nameBuf, 0, nameLen);
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index++;
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StringBuilder numStr = new StringBuilder(5);
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while (mem.get(JAVA_BYTE, index) != '\n') {
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if (mem.get(JAVA_BYTE, index) != '.') {
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numStr.append((char) mem.get(JAVA_BYTE, index));
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}
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index++;
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}
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index++;
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int num = Integer.parseInt(numStr.toString());
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var entry = new HashMap<String, StationStat>(1);
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entry.put(name, new StationStat(1, num, num, num));
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report.accept(entry);
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}
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}
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static class ProcessorThread extends Thread {
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static final int NUM_BUCKETS = 1024;
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static final int BUCKET_MASK = 0x3ff;
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static final int BUCKET_SIZE = 16;
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// n-way hash table state
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// 16 buckets, then 16 name pointers
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private final short[] hashTable = new short[2 * BUCKET_SIZE * NUM_BUCKETS];
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// storage of station name keys for hash collision check
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private final byte[] nameTable = new byte[MAX_UNIQUE_STATIONS * (MAX_STATION_NAME_LEN + 1)];
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// values for the hash key stable
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private final short[] stationIndexes = new short[BUCKET_SIZE * NUM_BUCKETS];
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private final int[] nextNamePos = { 0 };
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private final int[] nextStationIndex = { 0 };
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// Accumulator for (10s, 1s, (count*-2), .1s) per station
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private final long[] accumulators = new long[4 * MAX_UNIQUE_STATIONS];
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// min and max per station
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private final int[] minMax = new int[2 * MAX_UNIQUE_STATIONS];
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private final Queue<Segment> segments;
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private final FileChannel channel;
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private final Consumer<Map<String, StationStat>> report;
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ProcessorThread(Queue<Segment> segments, FileChannel channel, Consumer<Map<String, StationStat>> report) {
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this.segments = segments;
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this.channel = channel;
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this.report = report;
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for (int i = 0; i < minMax.length; i += 2) {
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minMax[i] = Integer.MAX_VALUE;
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minMax[i + 1] = Integer.MIN_VALUE;
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}
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}
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@Override
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public void run() {
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try {
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while (true) {
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var segment = segments.poll();
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if (segment == null) {
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break;
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}
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int startMargin = segment.start == 0 ? 0 : 1;
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int endMargin = 64;
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try (var arena = Arena.ofConfined()) {
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var mem = channel.map(FileChannel.MapMode.READ_ONLY, segment.start - startMargin, segment.len + endMargin + startMargin, arena);
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processChunk(mem, startMargin, segment.len + startMargin, hashTable, nameTable, stationIndexes, minMax, accumulators, nextNamePos, nextStationIndex);
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}
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}
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report.accept(decodeResult(hashTable, nameTable, stationIndexes, accumulators, minMax));
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} catch (IOException e) {
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System.err.println(STR."I/O Exception: \{e}");
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throw new RuntimeException(e);
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}
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}
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private static void processChunk(MemorySegment mem, int startPos, int endPos, short[] hashTable, byte[] nameTable, short[] stationIndexes, int[] minMax,
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long[] accumulators, int[] nextNamePos, int[] nextStationIndex) {
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int index = scanForStartPos(mem, startPos);
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var primeVec = IntVector.fromArray(NAME_HASH_SPECIES, HASH_PRIMES, 0);
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while (index < endPos) {
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var lineVec = ByteVector.fromMemorySegment(LINE_SCAN_SPECIES, mem, index, ByteOrder.LITTLE_ENDIAN);
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int numPos = lineVec.eq((byte) ';').firstTrue() + 1;
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int nlPos = 0;
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int stationIndex;
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if (numPos != LINE_SCAN_LEN + 1) {
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// Fast path, station name fits in one SIMD register
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nlPos = lineVec.eq((byte) '\n').firstTrue();
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if (nlPos == LINE_SCAN_LEN) {
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while (mem.get(JAVA_BYTE, index + nlPos) != '\n') {
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nlPos++;
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}
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}
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var nameVec = lineVec.and(ByteVector.fromArray(LINE_SCAN_SPECIES, PREFIX_MASK, 33 - numPos));
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int nameHash = nameVec.reinterpretAsInts().mul(primeVec).reduceLanes(VectorOperators.ADD);
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stationIndex = fastLookupHash(nameHash, nameVec, hashTable, nameTable, stationIndexes, nextNamePos, nextStationIndex);
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}
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else {
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// Slow path, station name larger than SIMD register
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while (mem.get(JAVA_BYTE, index + numPos - 1) != ';')
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numPos++;
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while (mem.get(JAVA_BYTE, index + nlPos) != '\n')
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nlPos++;
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int nameHash = lineVec.reinterpretAsInts().mul(primeVec).reduceLanes(VectorOperators.ADD);
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for (int i = LINE_SCAN_LEN; i < numPos - 1; i++) {
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nameHash = nameHash * 33 + mem.get(JAVA_BYTE, index + i);
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}
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stationIndex = lookupHash(nameHash, mem.asSlice(index, numPos - 1), hashTable, nameTable, stationIndexes, nextNamePos, nextStationIndex);
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}
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boolean isNegative = mem.get(JAVA_BYTE, index + numPos) == '-';
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// format; 0: 9.9, 1: 99.9, 2: -9.9, 3: -99.9
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int numFormat = nlPos - numPos - 3 + (isNegative ? 1 : 0);
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// accumulate sums for mean
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var numPartsVec = ByteVector.fromMemorySegment(ByteVector.SPECIES_128, mem, index + nlPos - 4, ByteOrder.LITTLE_ENDIAN)
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.sub((byte) '0')
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.convert(VectorOperators.B2I, 0);
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var multiplyVec = IntVector.fromArray(IntVector.SPECIES_128, DIGIT_MULTIPLIERS, 4 * numFormat);
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var toAdd = numPartsVec.mul(multiplyVec).castShape(ACCUMULATOR_SPECIES, 0);
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var acc = LongVector.fromArray(ACCUMULATOR_SPECIES, accumulators, 4 * stationIndex);
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acc.add(toAdd).intoArray(accumulators, 4 * stationIndex);
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// record min/max
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// encode ASCII value to sortable format without parsing
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int encoded = (mem.get(BIG_ENDIAN_INT, index + nlPos - 4) & DIGIT_MASK[numFormat]) ^ DIGIT_FLIPS[numFormat];
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minMax[2 * stationIndex] = Math.min(minMax[2 * stationIndex], encoded);
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minMax[2 * stationIndex + 1] = Math.max(minMax[2 * stationIndex + 1], encoded);
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index += nlPos + 1;
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}
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}
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// Look up name that fits in a vector
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private static int fastLookupHash(int nameHash, ByteVector nameVec, short[] hashTable, byte[] nameTable, short[] stationIndexes, int[] nextNamePos,
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int[] nextStationIndex) {
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int bucketIdx = nameHash & BUCKET_MASK;
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short shortHash = (short) (0x8000 | (nameHash >> 16));
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// Look up the station name to find the index
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while (true) {
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var bucketVec = ShortVector.fromArray(HASH_LOOKUP_SPECIES, hashTable, 2 * BUCKET_SIZE * bucketIdx);
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var bucketPos = bucketVec.eq(shortHash).firstTrue();
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if (bucketPos != HASH_LOOKUP_SPECIES.length()) {
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int slotNamePos = 32 * Short.toUnsignedInt(hashTable[2 * BUCKET_SIZE * bucketIdx + BUCKET_SIZE + bucketPos]);
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var slotNameVec = ByteVector.fromArray(LINE_SCAN_SPECIES, nameTable, slotNamePos);
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if (nameVec.eq(slotNameVec).allTrue()) {
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// Hit
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return stationIndexes[BUCKET_SIZE * bucketIdx + bucketPos];
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}
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else {
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bucketPos = handleHashCollision(shortHash, bucketIdx, MemorySegment.ofArray(nameVec.toArray()), hashTable, nameTable);
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if (bucketPos != -1) {
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return stationIndexes[BUCKET_SIZE * bucketIdx + bucketPos];
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}
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}
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}
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var emptyPos = bucketVec.eq((short) 0).firstTrue();
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if (emptyPos != HASH_LOOKUP_SPECIES.length()) {
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// Miss, insert
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int stationIndex = nextStationIndex[0]++;
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nameVec.intoArray(nameTable, nextNamePos[0]);
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hashTable[2 * BUCKET_SIZE * bucketIdx + emptyPos] = shortHash;
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hashTable[2 * BUCKET_SIZE * bucketIdx + BUCKET_SIZE + emptyPos] = (short) (nextNamePos[0] / 32);
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stationIndexes[BUCKET_SIZE * bucketIdx + emptyPos] = (short) stationIndex;
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nextNamePos[0] += nameVec.length();
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return stationIndex;
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}
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// Try next bucket
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bucketIdx = (bucketIdx + 1) & BUCKET_MASK;
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}
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}
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// Look up long name
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private static int lookupHash(int nameHash, MemorySegment nameSeg, short[] hashTable, byte[] nameTable, short[] stationIndexes, int[] nextNamePos,
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int[] nextStationIndex) {
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int bucketIdx = nameHash & BUCKET_MASK;
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short shortHash = (short) (0x8000 | (nameHash >> 16));
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// Look up the station name to find the index
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while (true) {
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var bucketVec = ShortVector.fromArray(HASH_LOOKUP_SPECIES, hashTable, 2 * BUCKET_SIZE * bucketIdx);
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var bucketPos = bucketVec.eq(shortHash).firstTrue();
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if (bucketPos != HASH_LOOKUP_SPECIES.length()) {
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int slotNamePos = 32 * Short.toUnsignedInt(hashTable[2 * BUCKET_SIZE * bucketIdx + BUCKET_SIZE + bucketPos]);
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boolean match = true;
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for (int i = 0; i < nameSeg.byteSize(); i++) {
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if (nameSeg.get(JAVA_BYTE, i) != nameTable[slotNamePos + i]) {
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match = false;
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}
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}
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match = match && nameTable[slotNamePos + (int) nameSeg.byteSize()] == '\0';
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if (match) {
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// Hit
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return stationIndexes[BUCKET_SIZE * bucketIdx + bucketPos];
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}
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else {
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bucketPos = handleHashCollision(shortHash, bucketIdx, nameSeg, hashTable, nameTable);
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if (bucketPos != -1) {
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return stationIndexes[BUCKET_SIZE * bucketIdx + bucketPos];
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}
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}
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}
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var emptyPos = bucketVec.eq((short) 0).firstTrue();
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if (emptyPos != HASH_LOOKUP_SPECIES.length()) {
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// Miss, insert
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int stationIndex = nextStationIndex[0]++;
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hashTable[2 * BUCKET_SIZE * bucketIdx + emptyPos] = shortHash;
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hashTable[2 * BUCKET_SIZE * bucketIdx + BUCKET_SIZE + emptyPos] = (short) (nextNamePos[0] / 32);
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stationIndexes[BUCKET_SIZE * bucketIdx + emptyPos] = (short) stationIndex;
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for (int i = 0; i < nameSeg.byteSize(); i++) {
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nameTable[nextNamePos[0]++] = nameSeg.get(JAVA_BYTE, i);
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}
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nameTable[nextNamePos[0]++] = '\0';
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while (nextNamePos[0] % 32 != 0)
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nextNamePos[0]++;
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return stationIndex;
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}
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// Try next bucket
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bucketIdx = (bucketIdx + 1) & BUCKET_MASK;
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}
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}
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private static int handleHashCollision(short shortHash, int bucketIdx, MemorySegment nameSeg, short[] hashTable, byte[] nameTable) {
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for (int i = 0; i < BUCKET_SIZE; i++) {
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if (hashTable[2 * BUCKET_SIZE * bucketIdx + i] == shortHash) {
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int namePos = 32 * Short.toUnsignedInt(hashTable[2 * BUCKET_SIZE * bucketIdx + BUCKET_SIZE + i]);
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if (Arrays.equals(nameSeg.toArray(JAVA_BYTE), Arrays.copyOfRange(nameTable, namePos, namePos + (int) nameSeg.byteSize()))
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&& nameTable[namePos + (int) nameSeg.byteSize()] == '\0') {
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return i;
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}
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}
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}
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return -1;
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}
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}
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// Find next record
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private static int scanForStartPos(MemorySegment mem, int startPos) {
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if (startPos == 0) {
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return startPos;
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}
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while (mem.get(JAVA_BYTE, startPos - 1) != '\n') {
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startPos++;
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}
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return startPos;
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}
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// Decode the accumulator values to StationStats
|
||||
private static Map<String, StationStat> decodeResult(short[] hashTable, byte[] nameTable, short[] stationIndexes, long[] accumulators, int[] minMax) {
|
||||
var result = new HashMap<String, StationStat>(MAX_UNIQUE_STATIONS);
|
||||
for (int i = 0; i < hashTable.length; i += 32) {
|
||||
for (int j = 0; j < 16; j++) {
|
||||
if (hashTable[i + j] != 0) {
|
||||
int namePos = 32 * Short.toUnsignedInt(hashTable[i + j + 16]);
|
||||
int nameLen = 1;
|
||||
while (nameTable[namePos + nameLen] != '\0') {
|
||||
nameLen++;
|
||||
}
|
||||
int stationIdx = stationIndexes[i / 2 + j];
|
||||
// Number of '-2' valued dots seen
|
||||
long count = accumulators[4 * stationIdx + 2] / -2;
|
||||
long total = accumulators[4 * stationIdx];
|
||||
total += accumulators[4 * stationIdx + 1];
|
||||
total += accumulators[4 * stationIdx + 3];
|
||||
int min = decodeInteger(minMax[2 * stationIdx]);
|
||||
int max = decodeInteger(minMax[2 * stationIdx + 1]);
|
||||
result.put(new String(nameTable, namePos, nameLen), new StationStat(count, total, min, max));
|
||||
}
|
||||
}
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
private static int decodeInteger(int encoded) {
|
||||
int mask = encoded >> 31;
|
||||
int orig = (encoded ^ mask) & 0x7fffffff;
|
||||
int val = (orig & 0xff) + ((orig >> 16) & 0xff) * 10 + ((orig >> 24) & 0xff) * 100;
|
||||
return val * (mask | 1);
|
||||
}
|
||||
|
||||
private static void printResult(Map<String, StationStat> stats) {
|
||||
System.out.print("{");
|
||||
System.out.print(
|
||||
stats.keySet().stream().sorted()
|
||||
.map(key -> {
|
||||
var s = stats.get(key);
|
||||
return STR."\{key}=\{s}";
|
||||
})
|
||||
.collect(Collectors.joining(", "))
|
||||
);
|
||||
System.out.println("}");
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user