First version of implementation - omarchenko4j (#222)
* First version of implementation * Fixes after running script test
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Oleh Marchenko
GitHub
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e1ae96f297
23
calculate_average_omarchenko4j.sh
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23
calculate_average_omarchenko4j.sh
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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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# Uncomment below to use sdk
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# source "$HOME/.sdkman/bin/sdkman-init.sh"
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# sdk use java 21.0.1-graal 1>&2
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JAVA_OPTS="--enable-preview"
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time java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_omarchenko4j
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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.lang.foreign.Arena;
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import java.lang.foreign.MemorySegment;
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import java.lang.foreign.ValueLayout;
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import java.nio.channels.FileChannel;
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import java.nio.channels.FileChannel.MapMode;
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import java.nio.file.Paths;
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import java.nio.file.StandardOpenOption;
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import java.util.ArrayList;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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import java.util.TreeMap;
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import java.util.concurrent.Callable;
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import java.util.concurrent.ExecutionException;
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import java.util.concurrent.Executors;
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public class CalculateAverage_omarchenko4j {
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private static final String FILE = "./measurements.txt";
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private static final int NUMBER_OF_CORES = Runtime.getRuntime().availableProcessors();
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private static final int MAX_LINE_SIZE = 128;
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public static void main(String[] args) throws IOException, InterruptedException, ExecutionException {
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try (var file = FileChannel.open(Paths.get(FILE), StandardOpenOption.READ)) {
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var fileSize = file.size();
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try (var arena = Arena.ofShared()) {
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var segment = file.map(MapMode.READ_ONLY, 0, fileSize, arena);
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var tasks = sliceIntoTasks(segment);
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try (var executor = Executors.newFixedThreadPool(Math.min(tasks.size(), NUMBER_OF_CORES))) {
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var futures = executor.invokeAll(tasks);
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var measurements = new TreeMap<String, Aggregator>(String::compareTo);
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for (var future : futures) {
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var result = future.get();
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for (var entry : result.entrySet()) {
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var station = entry.getKey();
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var a1 = entry.getValue();
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var a2 = measurements.get(station);
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if (a2 != null) {
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a1.merge(a2);
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}
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measurements.put(station, a1);
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}
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}
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System.out.println(measurements);
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}
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}
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}
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}
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private static List<Task> sliceIntoTasks(MemorySegment segment) {
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var tasks = new ArrayList<Task>(NUMBER_OF_CORES);
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var segmentSize = segment.byteSize();
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var chunkSize = segmentSize / NUMBER_OF_CORES;
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if (chunkSize < (long) NUMBER_OF_CORES * MAX_LINE_SIZE) {
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return List.of(new Task(segment, 0, segmentSize));
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}
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long offsetStart = 0;
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for (int coreNumber = 1; coreNumber <= NUMBER_OF_CORES; coreNumber++) {
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long offsetEnd = chunkSize * coreNumber;
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while (offsetEnd < segmentSize) {
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var b = segment.get(ValueLayout.JAVA_BYTE, offsetEnd);
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offsetEnd++;
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if (b == '\n') {
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break;
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}
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}
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tasks.add(new Task(segment, offsetStart, offsetEnd));
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offsetStart = offsetEnd;
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}
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return tasks;
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}
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private static class Task implements Callable<Map<String, Aggregator>> {
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private static final byte SEPARATOR = ';';
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private static final byte END_LINE = '\n';
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private final MemorySegment segment;
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private final long startOffset;
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private final long endOffset;
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private Task(MemorySegment segment, long startOffset, long endOffset) {
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this.segment = segment;
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this.startOffset = startOffset;
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this.endOffset = endOffset;
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}
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@Override
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public Map<String, Aggregator> call() {
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var measurements = new HashMap<String, Aggregator>(512);
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int startIndex = 0;
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int separatorIndex = 0;
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int endIndex = 0;
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var buffer = new byte[MAX_LINE_SIZE];
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int bufferIndex = 0;
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for (long offset = startOffset; offset < endOffset; offset++) {
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var b = segment.get(ValueLayout.JAVA_BYTE, offset);
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buffer[bufferIndex] = b;
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bufferIndex++;
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if (b == SEPARATOR) {
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separatorIndex = bufferIndex - 1;
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continue;
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}
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if (b == END_LINE) {
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endIndex = bufferIndex - 1;
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var station = new String(buffer, startIndex, separatorIndex);
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var value = getDouble(buffer, separatorIndex + 1, endIndex - separatorIndex - 1);
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measurements.computeIfAbsent(station, ignored -> new Aggregator()).addValue(value);
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bufferIndex = 0;
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}
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}
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return measurements;
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}
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private static final byte MINUS = '-';
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private static final byte ZERO = '0';
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private double getDouble(byte[] buffer, int offset, int length) {
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if (length == 4) {
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if (buffer[offset] == MINUS) {
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int value;
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value = buffer[offset + 1] - ZERO;
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value = (value * 10) + (buffer[offset + 3] - ZERO);
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value = -value;
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return value * .1D;
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}
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int value;
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value = buffer[offset] - ZERO;
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value = (value * 10) + (buffer[offset + 1] - ZERO);
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value = (value * 10) + (buffer[offset + 3] - ZERO);
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return value * .1D;
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}
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if (length == 3) {
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int value;
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value = buffer[offset] - ZERO;
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value = (value * 10) + (buffer[offset + 2] - ZERO);
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return value * .1D;
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}
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int value;
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value = buffer[offset + 1] - ZERO;
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value = (value * 10) + (buffer[offset + 2] - ZERO);
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value = (value * 10) + (buffer[offset + 4] - ZERO);
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value = -value;
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return value * .1D;
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}
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}
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public static class Aggregator {
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private double min = Double.POSITIVE_INFINITY;
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private double max = Double.NEGATIVE_INFINITY;
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private double sum;
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private long count;
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public void addValue(double value) {
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min = Math.min(min, value);
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max = Math.max(max, value);
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sum += value;
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count++;
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}
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public void merge(Aggregator aggregator) {
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if (aggregator.min < min) {
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min = aggregator.min;
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}
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if (aggregator.max > max) {
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max = aggregator.max;
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}
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sum += aggregator.sum;
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count += aggregator.count;
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}
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@Override
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public String toString() {
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return round(min) + "/" + round(sum / count) + "/" + round(max);
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}
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private double round(double value) {
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return Math.round(value * 10.0) / 10.0;
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}
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}
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}
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