Added dedicated reader (#493)
Started running perf, perhaps this helps. No idea how to use it yet
This commit is contained in:
Roy van Rijn
GitHub
parent
f409fe0815
commit
7c983f3d66
@ -22,7 +22,7 @@ sdk use java 21.0.1-graal 1>&2
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if [ ! -f target/CalculateAverage_royvanrijn_image ]; then
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JAVA_OPTS="--enable-preview -dsa"
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NATIVE_IMAGE_OPTS="--gc=epsilon -Ob -O3 -march=native --strict-image-heap $JAVA_OPTS"
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NATIVE_IMAGE_OPTS="--initialize-at-build-time=dev.morling.onebrc.CalculateAverage_royvanrijn --gc=epsilon -Ob -O3 -march=native --strict-image-heap $JAVA_OPTS"
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native-image $NATIVE_IMAGE_OPTS -cp target/average-1.0.0-SNAPSHOT.jar -o target/CalculateAverage_royvanrijn_image dev.morling.onebrc.CalculateAverage_royvanrijn
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fi
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@ -15,17 +15,15 @@
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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.reflect.Field;
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import java.nio.channels.FileChannel;
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import java.nio.charset.StandardCharsets;
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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.HashMap;
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import java.util.Map;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.stream.Collectors;
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import java.util.stream.IntStream;
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import sun.misc.Unsafe;
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@ -55,217 +53,501 @@ import sun.misc.Unsafe;
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* Remove writing to buffer: 1335 ms
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* Optimized collecting at the end: 1310 ms
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* Adding a lot of comments: priceless
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* Changed to flyweight byte[]: 1290 ms (adds even more Unsafe, was initially slower, now faster)
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* More LOC now parallel: 1260 ms (moved more to processMemoryArea, recombining in ConcurrentHashMap)
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* Storing only the address: 1240 ms (this is now faster, tried before, was slower)
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* Unrolling scan-loop: 1200 ms (seems to help, perhaps even more on target machine)
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* Adding more readable reader: 1300 ms (scores got worse on target machine anyway)
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*
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* Big thanks to Francesco Nigro, Thomas Wuerthinger, Quan Anh Mai for ideas.
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* I've ditched my M2 for an older x86-64 MacBook, this allows me to run `perf` and I'm trying to get lower numbers by trail and error.
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*
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* Big thanks to Francesco Nigro, Thomas Wuerthinger, Quan Anh Mai and many others for ideas.
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*
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* Follow me at: @royvanrijn
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*/
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public class CalculateAverage_royvanrijn {
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private static final String FILE = "./measurements.txt";
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// private static final String FILE = "src/test/resources/samples/measurements-1.txt";
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private static final Unsafe UNSAFE = initUnsafe();
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private static Unsafe initUnsafe() {
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try {
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final 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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public static void main(String[] args) throws Exception {
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// Calculate input segments.
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final int numberOfChunks = Runtime.getRuntime().availableProcessors();
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final long[] chunks = getSegments(numberOfChunks);
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final Map<String, Entry> measurements = HashMap.newHashMap(1 << 10);
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IntStream.range(0, chunks.length - 1)
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.mapToObj(chunkIndex -> processMemoryArea(chunks[chunkIndex], chunks[chunkIndex + 1]))
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.parallel()
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.forEachOrdered(repo -> { // make sure it's ordered, no concurrent map
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for (Entry entry : repo) {
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if (entry != null)
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measurements.merge(turnLongArrayIntoString(entry.data, entry.length), entry, Entry::mergeWith);
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}
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});
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System.out.print("{" +
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measurements.entrySet().stream().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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// Twice the processors, smoothens things out.
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private static final int PROCESSORS = Runtime.getRuntime().availableProcessors();
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/**
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* Simpler way to get the segments and launch parallel processing by thomaswue
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* Flyweight entry in a byte[], max 128 bytes.
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*
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* long: sum
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* int: min
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* int: max
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* int: count
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* byte: length
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* byte[]: cityname
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*/
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private static long[] getSegments(final int numberOfChunks) throws IOException {
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try (var fileChannel = FileChannel.open(Path.of(FILE), StandardOpenOption.READ)) {
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final long fileSize = fileChannel.size();
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final long segmentSize = (fileSize + numberOfChunks - 1) / numberOfChunks;
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final long[] chunks = new long[numberOfChunks + 1];
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final long mappedAddress = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, fileSize, Arena.global()).address();
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chunks[0] = mappedAddress;
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final long endAddress = mappedAddress + fileSize;
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for (int i = 1; i < numberOfChunks; ++i) {
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long chunkAddress = mappedAddress + i * segmentSize;
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// Align to first row start.
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while (chunkAddress < endAddress && UNSAFE.getByte(chunkAddress++) != '\n') {
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// nop
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}
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chunks[i] = Math.min(chunkAddress, endAddress);
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}
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chunks[numberOfChunks] = endAddress;
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return chunks;
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}
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}
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// ------------------------------------------------------------------------
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private static final int ENTRY_LENGTH = (Unsafe.ARRAY_BYTE_BASE_OFFSET);
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private static final int ENTRY_SUM = (ENTRY_LENGTH + Byte.BYTES);
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private static final int ENTRY_MIN = (ENTRY_SUM + Long.BYTES);
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private static final int ENTRY_MAX = (ENTRY_MIN + Integer.BYTES);
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private static final int ENTRY_COUNT = (ENTRY_MAX + Integer.BYTES);
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private static final int ENTRY_NAME = (ENTRY_COUNT + Integer.BYTES);
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private static final int ENTRY_NAME_8 = ENTRY_NAME + 8;
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private static final int ENTRY_NAME_16 = ENTRY_NAME + 16;
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// This is where I store the hashtable entry data in the "hot loop"
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// The long[] contains the name in bytes (yeah, confusing)
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// I've tried flyweight-ing, carrying all the data in a single byte[],
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// where you offset type-indices: min:int,max:int,count:int,etc.
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//
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// The performance was just a little worse than this simple class.
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static final class Entry {
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private int min, max, count;
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private byte length;
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private long sum;
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private final long[] data;
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Entry(final long[] data, byte length, int temp) {
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this.data = data;
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this.length = length;
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this.min = temp;
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this.max = temp;
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this.sum = temp;
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this.count = 1;
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}
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public void updateWith(int measurement) {
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min = Math.min(min, measurement);
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max = Math.max(max, measurement);
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sum += measurement;
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count++;
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}
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public Entry mergeWith(Entry entry) {
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min = Math.min(min, entry.min);
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max = Math.max(max, entry.max);
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sum += entry.sum;
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count += entry.count;
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return this;
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}
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public String toString() {
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return round(min) + "/" + round((1.0 * sum) / count) + "/" + round(max);
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}
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private static double round(double value) {
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return Math.round(value) / 10.0;
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}
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}
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// Only parse the String at the final end, when we have only the needed entries left that we need to output:
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private static String turnLongArrayIntoString(final long[] data, final int length) {
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// Create our target byte[]
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final byte[] bytes = new byte[length];
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// The power of magic allows us to just copy the memory in there.
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UNSAFE.copyMemory(data, Unsafe.ARRAY_LONG_BASE_OFFSET, bytes, Unsafe.ARRAY_BYTE_BASE_OFFSET, length);
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// And construct a String()
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return new String(bytes, StandardCharsets.UTF_8);
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}
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private static Entry createNewEntry(final long fromAddress, final int lengthLongs, final byte lengthBytes, final int temp) {
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// Make a copy of our working buffer, store this in a new Entry:
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final long[] bufferCopy = new long[lengthLongs];
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// Just copy everything over, bytes into the long[]
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UNSAFE.copyMemory(null, fromAddress, bufferCopy, Unsafe.ARRAY_BYTE_BASE_OFFSET, lengthBytes);
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return new Entry(bufferCopy, lengthBytes, temp);
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}
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private static final int TABLE_SIZE = 1 << 19;
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private static final int ENTRY_BASESIZE_WHITESPACE = ENTRY_NAME + 7; // with enough empty bytes to fill a long
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// ------------------------------------------------------------------------
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private static final int PREMADE_MAX_SIZE = 1 << 5; // pre-initialize some entries in memory, keep them close
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private static final int PREMADE_ENTRIES = 512; // amount of pre-created entries we should use
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private static final int TABLE_SIZE = 1 << 19; // large enough for the contest.
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private static final int TABLE_MASK = (TABLE_SIZE - 1);
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private static Entry[] processMemoryArea(final long fromAddress, final long toAddress) {
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public static void main(String[] args) throws Exception {
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int packedBytes;
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long hash;
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long ptr = fromAddress;
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long word;
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long mask;
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// Calculate input segments.
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final FileChannel fileChannel = FileChannel.open(Path.of(FILE), StandardOpenOption.READ);
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final long fileSize = fileChannel.size();
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final long segmentSize = (fileSize + PROCESSORS - 1) / PROCESSORS;
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final long mapAddress = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, fileSize, Arena.global()).address();
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final Entry[] table = new Entry[TABLE_SIZE];
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final Thread[] parallelThreads = new Thread[PROCESSORS - 1];
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// Go from start to finish address through the bytes:
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while (ptr < toAddress) {
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// This is where the entries will land:
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final ConcurrentHashMap<String, byte[]> measurements = new ConcurrentHashMap(1 << 10);
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final long startAddress = ptr;
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// We create separate threads for twice the amount of processors.
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long lastAddress = mapAddress;
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final long endOfFile = mapAddress + fileSize;
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for (int i = 0; i < PROCESSORS - 1; ++i) {
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packedBytes = 1;
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hash = 0;
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word = UNSAFE.getLong(ptr);
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mask = getDelimiterMask(word);
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final long fromAddress = lastAddress;
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final long toAddress = Math.min(endOfFile, fromAddress + segmentSize);
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// Removed writing to a buffer here, why would we, we know the address and we'll need to check there anyway.
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while (mask == 0) {
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// If the mask is zero, we have no ';'
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packedBytes++;
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// So we continue building the hash:
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hash ^= word;
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ptr += 8;
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final Thread thread = new Thread(() -> {
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// The actual work is done here:
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final byte[][] table = processMemoryArea(fromAddress, toAddress, fromAddress == mapAddress);
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// And getting a new value and mask:
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word = UNSAFE.getLong(ptr);
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mask = getDelimiterMask(word);
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for (byte[] entry : table) {
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if (entry != null) {
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measurements.merge(entryToName(entry), entry, CalculateAverage_royvanrijn::mergeEntry);
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}
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}
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});
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thread.start(); // start a.s.a.p.
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parallelThreads[i] = thread;
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lastAddress = toAddress;
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}
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// Use the current thread for the part of memory:
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final byte[][] table = processMemoryArea(lastAddress, mapAddress + fileSize, false);
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for (byte[] entry : table) {
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if (entry != null) {
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measurements.merge(entryToName(entry), entry, CalculateAverage_royvanrijn::mergeEntry);
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}
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}
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// Wait for all threads to finish:
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for (Thread thread : parallelThreads) {
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// Can we implement work-stealing? Not sure how...
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thread.join();
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}
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// If we don't reach start of file,
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System.out.print("{" +
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measurements.entrySet().stream().sorted(Map.Entry.comparingByKey())
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.map(entry -> entry.getKey() + '=' + entryValuesToString(entry.getValue()))
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.collect(Collectors.joining(", ")));
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System.out.println("}");
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// System.out.println(measurements.entrySet().stream().mapToLong(e -> UNSAFE.getInt(e.getValue(), ENTRY_COUNT + Unsafe.ARRAY_BYTE_BASE_OFFSET)).sum());
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}
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private static byte[] fillEntry(final byte[] entry, final long fromAddress, final int length, final int temp) {
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UNSAFE.putLong(entry, ENTRY_SUM, temp);
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UNSAFE.putInt(entry, ENTRY_MIN, temp);
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UNSAFE.putInt(entry, ENTRY_MAX, temp);
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UNSAFE.putInt(entry, ENTRY_COUNT, 1);
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UNSAFE.putByte(entry, ENTRY_LENGTH, (byte) length);
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UNSAFE.copyMemory(null, fromAddress, entry, ENTRY_NAME, length);
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return entry;
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}
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public static void updateEntry(final byte[] entry, final int temp) {
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int entryMin = UNSAFE.getInt(entry, ENTRY_MIN);
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int entryMax = UNSAFE.getInt(entry, ENTRY_MAX);
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entryMin = Math.min(temp, entryMin);
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entryMax = Math.max(temp, entryMax);
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long entrySum = UNSAFE.getLong(entry, ENTRY_SUM) + temp;
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int entryCount = UNSAFE.getInt(entry, ENTRY_COUNT) + 1;
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UNSAFE.putInt(entry, ENTRY_MIN, entryMin);
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UNSAFE.putInt(entry, ENTRY_MAX, entryMax);
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UNSAFE.putInt(entry, ENTRY_COUNT, entryCount);
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UNSAFE.putLong(entry, ENTRY_SUM, entrySum);
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}
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public static byte[] mergeEntry(final byte[] entry, final byte[] merge) {
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long sum = UNSAFE.getLong(merge, ENTRY_SUM);
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final int mergeMin = UNSAFE.getInt(merge, ENTRY_MIN);
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final int mergeMax = UNSAFE.getInt(merge, ENTRY_MAX);
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int count = UNSAFE.getInt(merge, ENTRY_COUNT);
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sum += UNSAFE.getLong(entry, ENTRY_SUM);
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int entryMin = UNSAFE.getInt(entry, ENTRY_MIN);
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int entryMax = UNSAFE.getInt(entry, ENTRY_MAX);
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count += UNSAFE.getInt(entry, ENTRY_COUNT);
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entryMin = Math.min(entryMin, mergeMin);
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entryMax = Math.max(entryMax, mergeMax);
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UNSAFE.putLong(entry, ENTRY_SUM, sum);
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UNSAFE.putInt(entry, ENTRY_MIN, entryMin);
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UNSAFE.putInt(entry, ENTRY_MAX, entryMax);
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UNSAFE.putInt(entry, ENTRY_COUNT, count);
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return entry;
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}
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private static String entryToName(final byte[] entry) {
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// Get the length from memory:
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int length = UNSAFE.getByte(entry, ENTRY_LENGTH);
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byte[] name = new byte[length];
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UNSAFE.copyMemory(entry, ENTRY_NAME, name, Unsafe.ARRAY_BYTE_BASE_OFFSET, length);
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// Create a new String with the existing byte[]:
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return new String(name, StandardCharsets.UTF_8);
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}
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private static String entryValuesToString(final byte[] entry) {
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return round(UNSAFE.getInt(entry, ENTRY_MIN))
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+ "/" +
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round((1.0 * UNSAFE.getLong(entry, ENTRY_SUM)) /
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UNSAFE.getInt(entry, ENTRY_COUNT))
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+ "/" +
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round(UNSAFE.getInt(entry, ENTRY_MAX));
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}
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// Print a piece of memory:
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// For debug.
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private static String printMemory(final Object target, final long address, int length) {
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String result = "";
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for (int i = 0; i < length; i++) {
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result += (char) UNSAFE.getByte(target, address + i);
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}
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return result;
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}
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// Print a piece of memory:
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// For debug.
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private static String printMemory(final long value, int length) {
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String result = "";
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for (int i = 0; i < length; i++) {
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result += (char) ((value >> (i << 3)) & 0xFF);
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}
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return result;
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}
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private static double round(final double value) {
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return Math.round(value) / 10.0;
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}
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private static final class Reader {
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private long ptr;
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private long delimiterMask;
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private long lastRead;
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private long lastReadMinOne;
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private long hash;
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private long entryStart;
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private long entryDelimiter;
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private final long endAddress;
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Reader(final long startAddress, final long endAddress, final boolean isFileStart) {
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this.ptr = startAddress;
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this.endAddress = endAddress;
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// Adjust start to next delimiter:
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if (!isFileStart) {
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ptr--;
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while (ptr < endAddress) {
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if (UNSAFE.getByte(ptr++) == '\n') {
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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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private void processStart() {
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hash = 0;
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entryStart = ptr;
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}
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private boolean hasNext() {
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return (ptr < endAddress);
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}
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private static final long DELIMITER_MASK = 0x3B3B3B3B3B3B3B3BL;
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private boolean readFirst() {
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lastRead = UNSAFE.getLong(ptr);
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final long match = lastRead ^ DELIMITER_MASK;
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delimiterMask = (match - 0x0101010101010101L) & (~match & 0x8080808080808080L);
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return delimiterMask == 0;
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}
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private boolean readNext() {
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lastReadMinOne = lastRead;
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return readFirst();
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}
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private void processName() {
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hash ^= lastRead;
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ptr += 8;
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}
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private int processEndAndGetTemperature() {
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processFinalBytes();
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finalizeHash();
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finalizeDelimiter();
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return readTemperature();
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}
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private void processFinalBytes() {
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// Shift and read the last bytes:
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lastRead &= ((delimiterMask >>> 7) - 1);
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}
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private void finalizeHash() {
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||||
// Finalize hash:
|
||||
hash ^= lastRead;
|
||||
hash ^= hash >> 32;
|
||||
hash ^= hash >> 17; // extra entropy
|
||||
}
|
||||
|
||||
private void finalizeDelimiter() {
|
||||
// Found delimiter:
|
||||
final int delimiterByte = Long.numberOfTrailingZeros(mask);
|
||||
final long delimiterAddress = ptr + (delimiterByte >> 3);
|
||||
entryDelimiter = ptr + (Long.numberOfTrailingZeros(delimiterMask) >> 3);
|
||||
}
|
||||
|
||||
// Finish the masks and hash:
|
||||
final long partialWord = word & ((mask >>> 7) - 1);
|
||||
hash ^= partialWord;
|
||||
private static final long DOT_BITS = 0x10101000;
|
||||
private static final long MAGIC_MULTIPLIER = (100 * 0x1000000 + 10 * 0x10000 + 1);
|
||||
|
||||
// Read a long value from memory starting from the delimiter + 1, the number part:
|
||||
final long numberBytes = UNSAFE.getLong(delimiterAddress + 1);
|
||||
final long invNumberBytes = ~numberBytes;
|
||||
// Awesome idea of merykitty:
|
||||
private int readTemperature() {
|
||||
// This is the number part: X.X, -X.X, XX.x or -XX.X
|
||||
long numberBytes = UNSAFE.getLong(entryDelimiter + 1);
|
||||
long invNumberBytes = ~numberBytes;
|
||||
|
||||
// Adjust our pointer
|
||||
final int decimalSepPos = Long.numberOfTrailingZeros(invNumberBytes & DOT_BITS);
|
||||
ptr = delimiterAddress + (decimalSepPos >> 3) + 4;
|
||||
int dotPosition = Long.numberOfTrailingZeros(invNumberBytes & DOT_BITS);
|
||||
|
||||
// Calculate the final hash and index of the table:
|
||||
int intHash = (int) (hash ^ (hash >> 32));
|
||||
intHash = intHash ^ (intHash >> 17);
|
||||
int index = intHash & TABLE_MASK;
|
||||
// Update the pointer here, bit awkward, but we have all the data
|
||||
ptr = entryDelimiter + (dotPosition >> 3) + 4;
|
||||
|
||||
int min28 = (28 - dotPosition);
|
||||
// Calculates the sign
|
||||
final long signed = (invNumberBytes << 59) >> 63;
|
||||
final long minusFilter = ~(signed & 0xFF);
|
||||
// Use the pre-calculated decimal position to adjust the values
|
||||
long digits = ((numberBytes & minusFilter) << min28) & 0x0F000F0F00L;
|
||||
// Multiply by a magic (100 * 0x1000000 + 10 * 0x10000 + 1), to get the result
|
||||
final long absValue = ((digits * MAGIC_MULTIPLIER) >>> 32) & 0x3FF;
|
||||
// And perform abs()
|
||||
return (int) ((absValue + signed) ^ signed); // non-patented method of doing the same trick
|
||||
}
|
||||
|
||||
private boolean matchesEntryFull(final byte[] entry) {
|
||||
int longs = (int) (entryDelimiter - entryStart) >> 3;
|
||||
int step = 0;
|
||||
for (int i = 0; i < longs - 2; i++) {
|
||||
if (UNSAFE.getLong(entryStart + step) != UNSAFE.getLong(entry, ENTRY_NAME + step)) {
|
||||
return false;
|
||||
}
|
||||
step += 8;
|
||||
}
|
||||
if (lastReadMinOne != UNSAFE.getLong(entry, (ENTRY_NAME_8) + step)) {
|
||||
return false;
|
||||
}
|
||||
if (lastRead != UNSAFE.getLong(entry, (ENTRY_NAME_16) + step)) {
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
|
||||
}
|
||||
|
||||
private boolean matchesEntryMedium(final byte[] entry) {
|
||||
if (UNSAFE.getLong(entryStart) != UNSAFE.getLong(entry, ENTRY_NAME)) {
|
||||
return false;
|
||||
}
|
||||
if (lastReadMinOne != UNSAFE.getLong(entry, ENTRY_NAME_8)) {
|
||||
return false;
|
||||
}
|
||||
if (lastRead != UNSAFE.getLong(entry, ENTRY_NAME_16)) {
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
private boolean matchesEntryShort(final byte[] entry) {
|
||||
if (lastReadMinOne != UNSAFE.getLong(entry, ENTRY_NAME)) {
|
||||
return false;
|
||||
}
|
||||
if (lastRead != UNSAFE.getLong(entry, ENTRY_NAME_8)) {
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
private boolean matchesEnding(final byte[] entry) {
|
||||
return lastRead == UNSAFE.getLong(entry, ENTRY_NAME);
|
||||
}
|
||||
|
||||
private int length() {
|
||||
return (int) (entryDelimiter - entryStart);
|
||||
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
private static byte[][] processMemoryArea(final long startAddress, final long endAddress, boolean isFileStart) {
|
||||
|
||||
final byte[][] table = new byte[TABLE_SIZE][];
|
||||
final byte[][] preConstructedEntries = new byte[PREMADE_ENTRIES][ENTRY_BASESIZE_WHITESPACE + PREMADE_MAX_SIZE];
|
||||
|
||||
final Reader reader = new Reader(startAddress, endAddress, isFileStart);
|
||||
|
||||
byte[] entry;
|
||||
int entryCount = 0;
|
||||
|
||||
// Find the correct starting position
|
||||
while (reader.hasNext()) {
|
||||
|
||||
reader.processStart();
|
||||
|
||||
if (!reader.readFirst()) {
|
||||
int temperature = reader.processEndAndGetTemperature();
|
||||
|
||||
// Find or insert the entry:
|
||||
int index = (int) (reader.hash & TABLE_MASK);
|
||||
while (true) {
|
||||
Entry tableEntry = table[index];
|
||||
if (tableEntry == null) {
|
||||
final int temp = extractTemp(decimalSepPos, invNumberBytes, numberBytes);
|
||||
// Create a new entry:
|
||||
final byte length = (byte) (delimiterAddress - startAddress);
|
||||
table[index] = createNewEntry(startAddress, packedBytes, length, temp);
|
||||
entry = table[index];
|
||||
if (entry == null) {
|
||||
int length = reader.length();
|
||||
byte[] entryBytes = (entryCount < PREMADE_ENTRIES) ? preConstructedEntries[entryCount++]
|
||||
: new byte[ENTRY_BASESIZE_WHITESPACE + length];
|
||||
table[index] = fillEntry(entryBytes, reader.entryStart, length, temperature);
|
||||
break;
|
||||
}
|
||||
// Don't bother re-checking things here like hash or length.
|
||||
// we'll need to check the content anyway if it's a hit, which is most times
|
||||
else if (memoryEqualsEntry(startAddress, tableEntry.data, partialWord, packedBytes)) {
|
||||
// temperature, you're not temporary my friend
|
||||
final int temp = extractTemp(decimalSepPos, invNumberBytes, numberBytes);
|
||||
// No differences, same entry:
|
||||
tableEntry.updateWith(temp);
|
||||
else if (reader.matchesEnding(entry)) {
|
||||
updateEntry(entry, temperature);
|
||||
break;
|
||||
}
|
||||
// Move to the next in the table, linear probing:
|
||||
else {
|
||||
// Move to the next index
|
||||
index = (index + 1) & TABLE_MASK;
|
||||
}
|
||||
}
|
||||
}
|
||||
else {
|
||||
reader.processName();
|
||||
|
||||
if (!reader.readNext()) {
|
||||
|
||||
int temperature = reader.processEndAndGetTemperature();
|
||||
|
||||
// Find or insert the entry:
|
||||
int index = (int) (reader.hash & TABLE_MASK);
|
||||
while (true) {
|
||||
entry = table[index];
|
||||
if (entry == null) {
|
||||
int length = reader.length();
|
||||
byte[] entryBytes = (entryCount < PREMADE_ENTRIES) ? preConstructedEntries[entryCount++]
|
||||
: new byte[ENTRY_BASESIZE_WHITESPACE + length];
|
||||
table[index] = fillEntry(entryBytes, reader.entryStart, length, temperature);
|
||||
break;
|
||||
}
|
||||
else if (reader.matchesEntryShort(entry)) {
|
||||
updateEntry(entry, temperature);
|
||||
break;
|
||||
}
|
||||
else {
|
||||
// Move to the next index
|
||||
index = (index + 1) & TABLE_MASK;
|
||||
}
|
||||
}
|
||||
}
|
||||
else {
|
||||
reader.processName();
|
||||
|
||||
if (!reader.readNext()) {
|
||||
int temperature = reader.processEndAndGetTemperature();
|
||||
|
||||
// Find or insert the entry:
|
||||
int index = (int) (reader.hash & TABLE_MASK);
|
||||
while (true) {
|
||||
entry = table[index];
|
||||
if (entry == null) {
|
||||
int length = reader.length();
|
||||
byte[] entryBytes = (entryCount < PREMADE_ENTRIES) ? preConstructedEntries[entryCount++]
|
||||
: new byte[ENTRY_BASESIZE_WHITESPACE + length];
|
||||
table[index] = fillEntry(entryBytes, reader.entryStart, length, temperature);
|
||||
break;
|
||||
}
|
||||
else if (reader.matchesEntryMedium(entry)) {
|
||||
updateEntry(entry, temperature);
|
||||
break;
|
||||
}
|
||||
else {
|
||||
// Move to the next index
|
||||
index = (index + 1) & TABLE_MASK;
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
else {
|
||||
|
||||
reader.processName();
|
||||
while (reader.readNext()) {
|
||||
reader.processName();
|
||||
}
|
||||
|
||||
int temperature = reader.processEndAndGetTemperature();
|
||||
|
||||
// Find or insert the entry:
|
||||
int index = (int) (reader.hash & TABLE_MASK);
|
||||
while (true) {
|
||||
entry = table[index];
|
||||
if (entry == null) {
|
||||
int length = reader.length();
|
||||
byte[] entryBytes = (length < PREMADE_MAX_SIZE && entryCount < PREMADE_ENTRIES) ? preConstructedEntries[entryCount++]
|
||||
: new byte[ENTRY_BASESIZE_WHITESPACE + length]; // with enough room
|
||||
table[index] = fillEntry(entryBytes, reader.entryStart, length, temperature);
|
||||
break;
|
||||
}
|
||||
else if (reader.matchesEntryFull(entry)) {
|
||||
updateEntry(entry, temperature);
|
||||
break;
|
||||
}
|
||||
else {
|
||||
// Move to the next index
|
||||
index = (index + 1) & TABLE_MASK;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
return table;
|
||||
}
|
||||
|
||||
@ -277,52 +559,16 @@ public class CalculateAverage_royvanrijn {
|
||||
* ---------------- BETTER SOFTWARE, FASTER --
|
||||
*
|
||||
* https://www.openvalue.eu/
|
||||
*
|
||||
* Made you look.
|
||||
*
|
||||
*/
|
||||
|
||||
private static final long DOT_BITS = 0x10101000;
|
||||
private static final long MAGIC_MULTIPLIER = (100 * 0x1000000 + 10 * 0x10000 + 1);
|
||||
|
||||
private static int extractTemp(final int decimalSepPos, final long invNumberBits, final long numberBits) {
|
||||
// Awesome idea of merykitty:
|
||||
int min28 = (28 - decimalSepPos);
|
||||
// Calculates the sign
|
||||
final long signed = (invNumberBits << 59) >> 63;
|
||||
final long minusFilter = ~(signed & 0xFF);
|
||||
// Use the pre-calculated decimal position to adjust the values
|
||||
final long digits = ((numberBits & minusFilter) << min28) & 0x0F000F0F00L;
|
||||
// Multiply by a magic (100 * 0x1000000 + 10 * 0x10000 + 1), to get the result
|
||||
final long absValue = ((digits * MAGIC_MULTIPLIER) >>> 32) & 0x3FF;
|
||||
// And perform abs()
|
||||
final int temp = (int) ((absValue + signed) ^ signed); // non-patented method of doing the same trick
|
||||
return temp;
|
||||
private static Unsafe initUnsafe() {
|
||||
try {
|
||||
final Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
|
||||
theUnsafe.setAccessible(true);
|
||||
return (Unsafe) theUnsafe.get(Unsafe.class);
|
||||
}
|
||||
catch (NoSuchFieldException | IllegalAccessException e) {
|
||||
throw new RuntimeException(e);
|
||||
}
|
||||
|
||||
private static final long SEPARATOR_PATTERN = 0x3B3B3B3B3B3B3B3BL;
|
||||
|
||||
// Takes a long and finds the bytes where this exact pattern is present.
|
||||
// Cool bit manipulation technique: SWAR (SIMD as a Register).
|
||||
private static long getDelimiterMask(final long word) {
|
||||
final long match = word ^ SEPARATOR_PATTERN;
|
||||
return (match - 0x0101010101010101L) & (~match & 0x8080808080808080L);
|
||||
// I've put some brackets separating the first and second part, this is faster.
|
||||
// Now they run simultaneous after 'match' is altered, instead of waiting on each other.
|
||||
}
|
||||
|
||||
/**
|
||||
* For case multiple hashes are equal (however unlikely) check the actual key (using longs)
|
||||
*/
|
||||
private static boolean memoryEqualsEntry(final long startAddress, final long[] entry, final long finalBytes, final int amountLong) {
|
||||
for (int i = 0; i < (amountLong - 1); i++) {
|
||||
int step = i << 3; // step by 8 bytes
|
||||
if (UNSAFE.getLong(startAddress + step) != entry[i])
|
||||
return false;
|
||||
}
|
||||
// If all previous 'whole' 8-packed byte-long values are equal
|
||||
// We still need to check the final bytes that don't fit.
|
||||
// and we've already calculated them for the hash.
|
||||
return finalBytes == entry[amountLong - 1];
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user