Experiment from entangled90
* single thread memory mapped file reader, pool of processors * cleanup of inner classes of MetricProcessor * doubles are parsed without external functions, strings are lazily created from byte arrays * remove load() MappedByteBuffer in memory * fixed handling of newline * fix a bug & correct locale used * MappedByteBuffer size set to 1MB * fixed rounding * Do not use ArrayBlockingQueue.offer since it drops elements when queue is full * MappedByteBuffer size = 32 MB
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calculate_average_entangled90.sh
Executable file
20
calculate_average_entangled90.sh
Executable file
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#!/bin/sh
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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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JAVA_OPTS=""
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time java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_entangled90
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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 java.io.IOException;
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import java.io.RandomAccessFile;
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import java.nio.ByteBuffer;
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import java.nio.MappedByteBuffer;
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import java.nio.channels.FileChannel;
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import java.nio.charset.StandardCharsets;
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import java.util.*;
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import java.util.concurrent.ArrayBlockingQueue;
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import java.util.concurrent.CountDownLatch;
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import java.util.concurrent.TimeUnit;
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import java.util.function.Consumer;
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import java.util.stream.Collectors;
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import static java.lang.Math.round;
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public class CalculateAverage_entangled90 {
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private static final String FILE = "./measurements.txt";
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public static final boolean DEBUG = false;
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public static void main(String[] args) throws IOException {
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Scanner scanner = new Scanner();
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long start = System.currentTimeMillis();
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PooledChunkProcessor chunkProcessor = new PooledChunkProcessor(Runtime.getRuntime().availableProcessors());
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scanner.scan(FILE, chunkProcessor, 0L, -1);
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long finish = System.currentTimeMillis();
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var map = chunkProcessor.result();
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map.printResults();
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if (DEBUG) {
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System.out.println("Took: " + TimeUnit.MILLISECONDS.toSeconds(finish - start) + "seconds");
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}
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}
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}
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class AggregatedProcessor {
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public double max = Double.NEGATIVE_INFINITY;
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public double min = Double.POSITIVE_INFINITY;
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private double sum = 0L;
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public long count = 0L;
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public void addMeasure(double value) {
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max = Math.max(max, value);
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min = Math.min(min, value);
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sum += value;
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count++;
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}
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public void combine(AggregatedProcessor processor) {
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max = Math.max(max, processor.max);
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min = Math.min(min, processor.min);
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sum += processor.sum;
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count += processor.count;
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}
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public double mean() {
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return sum / count;
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}
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private static double round(double d) {
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return Math.round(d * 10.0) / 10.0;
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}
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@Override
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public String toString() {
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return String.format(Locale.US, "%.1f/%.1f/%.1f", round(min), round(mean()), round(max));
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}
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}
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class ProcessorMap {
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Map<BytesWrapper, AggregatedProcessor> processors = new HashMap<>(1024);
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public void printResults() {
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System.out.println("Processed: " + processors.entrySet().stream().mapToLong(e -> e.getValue().count).sum());
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System.out.print("{");
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System.out.print(
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processors.entrySet().stream()
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.sorted(Map.Entry.comparingByKey()).map(Object::toString).collect(Collectors.joining(", ")));
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System.out.println("}");
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}
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public void addMeasure(BytesWrapper city, double value) {
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var processor = processors.get(city);
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if (processor == null) {
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processor = new AggregatedProcessor();
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processors.put(city, processor);
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}
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processor.addMeasure(value);
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}
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private void combine(BytesWrapper city, AggregatedProcessor processor) {
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var thisProcessor = processors.get(city);
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if (thisProcessor == null) {
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processors.put(city, processor);
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}
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else {
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thisProcessor.combine(processor);
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}
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}
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public static ProcessorMap combineAll(ProcessorMap... processors) {
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var result = new ProcessorMap();
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for (var p : processors) {
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for (var entry : p.processors.entrySet()) {
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result.combine(entry.getKey(), entry.getValue());
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}
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}
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return result;
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}
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}
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class PooledChunkProcessor implements Consumer<ByteBuffer> {
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private final ArrayBlockingQueue<ByteBuffer> queue;
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private final ProcessorMap[] results;
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private final CountDownLatch latch;
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private volatile boolean queueClosed = false;
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public PooledChunkProcessor(int n) {
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queue = new ArrayBlockingQueue<>(4 * 1024);
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results = new ProcessorMap[n];
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latch = new CountDownLatch(n);
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for (int i = 0; i < n; i++) {
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int finalI = i;
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var t = new Thread(() -> {
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var processor = new ChunkProcessor();
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while (!Thread.interrupted()) {
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try {
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var element = queue.poll(1, TimeUnit.MILLISECONDS);
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if (element != null)
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processor.processChunk(element);
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else if (queueClosed) {
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if (CalculateAverage_entangled90.DEBUG) {
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System.out.println("Queue closed, thread #" + finalI + " stopping");
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}
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break;
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}
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}
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catch (InterruptedException e) {
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break;
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}
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}
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results[finalI] = processor.processors;
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latch.countDown();
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});
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t.start();
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}
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}
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@Override
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public void accept(ByteBuffer byteBuffer) {
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try {
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queue.put(byteBuffer);
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}
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catch (InterruptedException e) {
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throw new RuntimeException(e);
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}
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}
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public ProcessorMap result() {
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try {
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queueClosed = true;
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latch.await();
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}
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catch (InterruptedException e) {
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e.printStackTrace();
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}
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return ProcessorMap.combineAll(results);
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}
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}
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class ChunkProcessor implements Consumer<ByteBuffer> {
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ProcessorMap processors = new ProcessorMap();
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public void processChunk(ByteBuffer bb) {
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while (processRow(bb)) {
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}
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}
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@Override
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public void accept(ByteBuffer byteBuffer) {
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processChunk(byteBuffer);
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}
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// true if you can continue
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// false if input is missing
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public boolean processRow(ByteBuffer bb) {
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int colonIdx = findSemiColon(bb);
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if (colonIdx < 0) {
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return false;
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}
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while (bb.get(bb.position()) == '\n') {
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bb.get();
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}
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var wrapper = wrapperFromBB(bb, colonIdx - bb.position());
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bb.position(colonIdx + 1);
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double value = parseDoubleNewLine(bb);
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processors.addMeasure(wrapper, value);
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return true;
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}
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private static BytesWrapper wrapperFromBB(ByteBuffer bb, int length) {
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var bytes = new byte[length];
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bb.get(bytes);
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return new BytesWrapper(bytes);
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}
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// don't advance bb
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private int findSemiColon(ByteBuffer bb) {
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for (int i = bb.position(); i < bb.limit(); i++) {
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if (bb.get(i) == (byte) ';')
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return i;
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}
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return -1;
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}
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// parses double until new line and advances buffer
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private static double parseDoubleNewLine(ByteBuffer bb) {
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int result = 0;
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int sign = 1;
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byte c;
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do {
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c = bb.get();
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switch (c) {
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case '-':
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sign = -1;
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break;
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case '.', ',', '\r', '\n':
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break;
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default:
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result = result * 10 + (c - '0');
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}
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} while (c != '\n' && bb.position() < bb.limit());
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return result * sign / 10.0;
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}
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}
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class Scanner {
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private static final int MAX_MAPPED_MEMORY = 32 * 1024 * 1024;
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public void scan(String fileName, Consumer<ByteBuffer> consumer, long offset, long len) throws IOException {
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try (var file = new RandomAccessFile(fileName, "r"); FileChannel channel = file.getChannel()) {
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int chunkId = 0;
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if (len < 0) {
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len = file.length();
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}
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while (true) {
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if (offset > 0) {
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file.seek(offset);
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}
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MappedByteBuffer bb = channel.map(FileChannel.MapMode.READ_ONLY, offset, Math.min(MAX_MAPPED_MEMORY, len - offset));
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var limitIdx = findLastNewLine(bb);
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bb.limit(limitIdx);
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// get last newline from the end
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consumer.accept(bb);
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chunkId++;
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offset += limitIdx;
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if (CalculateAverage_entangled90.DEBUG && chunkId % 10 == 0) {
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System.out.println(" read chunk " + chunkId + " at pointer " + offset + "(" + ((int) (offset * 100 / len)) + "%)");
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}
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if (offset >= len - 1) {
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break;
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}
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}
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}
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}
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public int findLastNewLine(ByteBuffer bb) {
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for (int i = bb.limit() - 1; i > bb.position(); i--) {
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if (bb.get(i) == '\n') {
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return i;
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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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class BytesWrapper implements Comparable<BytesWrapper> {
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private final byte[] bytes;
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public BytesWrapper(byte[] bytes) {
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this.bytes = bytes;
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}
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@Override
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public boolean equals(Object obj) {
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if (obj instanceof BytesWrapper) {
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return Arrays.equals(bytes, ((BytesWrapper) obj).bytes);
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}
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else {
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return false;
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}
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}
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@Override
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public int hashCode() {
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return Arrays.hashCode(bytes);
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}
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@Override
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public String toString() {
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return new String(bytes);
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}
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@Override
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public int compareTo(BytesWrapper bytesWrapper) {
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return this.toString().compareTo(bytesWrapper.toString());
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}
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}
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