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Updating Sam Pullara's entry
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@spullara
spullara authored Jan 4, 2024
1 parent c1954f6 commit 4af3253
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Showing 2 changed files with 152 additions and 171 deletions.
1 change: 1 addition & 0 deletions calculate_average_spullara.sh
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Expand Up @@ -17,5 +17,6 @@


JAVA_OPTS=""
sdk use java 21.0.1-graal
time java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_spullara

322 changes: 151 additions & 171 deletions src/main/java/dev/morling/onebrc/CalculateAverage_spullara.java
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Expand Up @@ -27,13 +27,10 @@
import java.util.List;
import java.util.TreeMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Consumer;
import java.util.function.Supplier;
import java.util.stream.Collectors;

public class CalculateAverage_spullara {
private static final String FILE = "./measurements.txt";
private static final String FILE = "./measurements.txt";

/*
* My results on this computer:
Expand All @@ -44,189 +41,172 @@ public class CalculateAverage_spullara {
*
*/

public static void main(String[] args) throws IOException, ExecutionException, InterruptedException {
var filename = args.length == 0 ? FILE : args[0];
var file = new File(filename);
long start = System.currentTimeMillis();

var totalLines = new AtomicInteger();
var results = getFileSegments(file).stream().map(segment -> {
var resultMap = new ByteArrayToResultMap();
long segmentEnd = segment.end();
try (var fileChannel = (FileChannel) Files.newByteChannel(Path.of(filename), StandardOpenOption.READ)) {
var bb = fileChannel.map(FileChannel.MapMode.READ_ONLY, segment.start(), segmentEnd - segment.start());
var buffer = new byte[64];
int lines = 0;
int startLine;
int limit = bb.limit();
while ((startLine = bb.position()) < limit) {
int currentPosition = startLine;
byte b;
int offset = 0;
while (currentPosition != segmentEnd && (b = bb.get(currentPosition++)) != ';') {
buffer[offset++] = b;
}
int temp = 0;
int negative = 1;
outer:
while (currentPosition != segmentEnd && (b = bb.get(currentPosition++)) != '\n') {
switch (b) {
case '-':
negative = -1;
case '.':
break;
case '\r':
currentPosition++;
break outer;
default:
temp = 10 * temp + (b - '0');
public static void main(String[] args) throws IOException, ExecutionException, InterruptedException {
long start = System.currentTimeMillis();
var filename = args.length == 0 ? FILE : args[0];
var file = new File(filename);

var resultsMap = getFileSegments(file).stream().map(segment -> {
var resultMap = new ByteArrayToResultMap();
long segmentEnd = segment.end();
try (var fileChannel = (FileChannel) Files.newByteChannel(Path.of(filename), StandardOpenOption.READ)) {
var bb = fileChannel.map(FileChannel.MapMode.READ_ONLY, segment.start(), segmentEnd - segment.start());
// Up to 100 characters for a city name
var buffer = new byte[100];
int startLine;
int limit = bb.limit();
while ((startLine = bb.position()) < limit) {
int currentPosition = startLine;
byte b;
int offset = 0;
int hash = 0;
while (currentPosition != segmentEnd && (b = bb.get(currentPosition++)) != ';') {
buffer[offset++] = b;
hash = 31 * hash + b;
}
int temp;
int negative = 1;
// Inspired by @yemreinci to unroll this even further
if (bb.get(currentPosition) == '-') {
negative = -1;
currentPosition++;
}
if (bb.get(currentPosition + 1) == '.') {
temp = negative * ((bb.get(currentPosition) - '0') * 10 + (bb.get(currentPosition + 2) - '0'));
currentPosition += 3;
}
else {
temp = negative * ((bb.get(currentPosition) - '0') * 100 + ((bb.get(currentPosition + 1) - '0') * 10 + (bb.get(currentPosition + 3) - '0')));
currentPosition += 4;
}
if (bb.get(currentPosition) == '\r') {
currentPosition++;
}
currentPosition++;
resultMap.putOrMerge(buffer, 0, offset, temp / 10.0, hash);
bb.position(currentPosition);
}
return resultMap;
}
}
temp *= negative;
double finalTemp = temp / 10.0;
resultMap.putOrMerge(buffer, 0, offset,
() -> new Result(finalTemp),
measurement -> merge(measurement, finalTemp, finalTemp, finalTemp, 1));
lines++;
bb.position(currentPosition);
catch (IOException e) {
throw new RuntimeException(e);
}
}).parallel().flatMap(partition -> partition.getAll().stream())
.collect(Collectors.toMap(e -> new String(e.key()), Entry::value, CalculateAverage_spullara::merge, TreeMap::new));

System.out.println(resultsMap);
}

private static List<FileSegment> getFileSegments(File file) throws IOException {
int numberOfSegments = Runtime.getRuntime().availableProcessors();
long fileSize = file.length();
long segmentSize = fileSize / numberOfSegments;
List<FileSegment> segments = new ArrayList<>(numberOfSegments);
// Pointless to split small files
if (segmentSize < 1_000_000) {
segments.add(new FileSegment(0, fileSize));
return segments;
}
totalLines.addAndGet(lines);
return resultMap;
} catch (IOException e) {
throw new RuntimeException(e);
}
}).parallel().toList();

var resultMap = results.stream()
.flatMap(partition -> partition.getAll().stream())
.collect(Collectors.toMap(e -> new String(e.key()), Entry::value, CalculateAverage_spullara::merge, TreeMap::new));

System.out.println("Time: " + (System.currentTimeMillis() - start) + "ms");
System.out.println("Lines processed: " + totalLines);
System.out.println(resultMap);
}

private static List<FileSegment> getFileSegments(File file) throws IOException {
int numberOfSegments = Runtime.getRuntime().availableProcessors();
long fileSize = file.length();
long segmentSize = fileSize / numberOfSegments;
List<FileSegment> segments = new ArrayList<>();
try (RandomAccessFile randomAccessFile = new RandomAccessFile(file, "r")) {
for (int i = 0; i < numberOfSegments; i++) {
long segStart = i * segmentSize;
long segEnd = (i == numberOfSegments - 1) ? fileSize : segStart + segmentSize;
segStart = findSegment(i, 0, randomAccessFile, segStart, segEnd);
segEnd = findSegment(i, numberOfSegments - 1, randomAccessFile, segEnd, fileSize);

segments.add(new FileSegment(segStart, segEnd));
}
try (RandomAccessFile randomAccessFile = new RandomAccessFile(file, "r")) {
for (int i = 0; i < numberOfSegments; i++) {
long segStart = i * segmentSize;
long segEnd = (i == numberOfSegments - 1) ? fileSize : segStart + segmentSize;
segStart = findSegment(i, 0, randomAccessFile, segStart, segEnd);
segEnd = findSegment(i, numberOfSegments - 1, randomAccessFile, segEnd, fileSize);

segments.add(new FileSegment(segStart, segEnd));
}
}
return segments;
}
return segments;
}

private static Result merge(Result v, Result value) {
return merge(v, value.min, value.max, value.sum, value.count);
}

private static Result merge(Result v, double value, double value1, double value2, long value3) {
v.min = Math.min(v.min, value);
v.max = Math.max(v.max, value1);
v.sum += value2;
v.count += value3;
return v;
}

private static long findSegment(int i, int skipSegment, RandomAccessFile raf, long location, long fileSize) throws IOException {
if (i != skipSegment) {
raf.seek(location);
while (location < fileSize) {
location++;
if (raf.read() == '\n')
break;
}

private static Result merge(Result v, Result value) {
return merge(v, value.min, value.max, value.sum, value.count);
}

private static Result merge(Result v, double value, double value1, double value2, long value3) {
v.min = Math.min(v.min, value);
v.max = Math.max(v.max, value1);
v.sum += value2;
v.count += value3;
return v;
}

private static long findSegment(int i, int skipSegment, RandomAccessFile raf, long location, long fileSize) throws IOException {
if (i != skipSegment) {
raf.seek(location);
while (location < fileSize) {
location++;
if (raf.read() == '\n')
break;
}
}
return location;
}
return location;
}
}

class Result {
double min, max, sum;
long count;

Result(double value) {
min = max = sum = value;
this.count = 1;
}
double min, max, sum;
long count;

@Override
public String toString() {
return round(min) + "/" + round(sum / count) + "/" + round(max);
}
Result(double value) {
min = max = sum = value;
this.count = 1;
}

double round(double v) {
return Math.round(v * 10.0) / 10.0;
}
@Override
public String toString() {
return round(min) + "/" + round(sum / count) + "/" + round(max);
}

}
double round(double v) {
return Math.round(v * 10.0) / 10.0;
}

record Pair(int slot, Result slotValue) {
}

record Entry(byte[] key, Result value) {
}
record Entry(byte[] key, Result value) {
}

record FileSegment(long start, long end) {
}
record FileSegment(long start, long end) {
}

class ByteArrayToResultMap {
public static final int MAPSIZE = 1024*128;
Result[] slots = new Result[MAPSIZE];
byte[][] keys = new byte[MAPSIZE][];

private int hashCode(byte[] a, int fromIndex, int length) {
int result = 0;
int end = fromIndex + length;
for (int i = fromIndex; i < end; i++) {
result = 31 * result + a[i];
}
return result;
}

private Pair getPair(byte[] key, int offset, int size) {
int hash = hashCode(key, offset, size);
int slot = hash & (slots.length - 1);
var slotValue = slots[slot];
// Linear probe for open slot
while (slotValue != null && (keys[slot].length != size || !Arrays.equals(keys[slot], 0, size, key, offset, size))) {
slot = (slot + 1) & (slots.length - 1);
slotValue = slots[slot];
}
return new Pair(slot, slotValue);
}

public void putOrMerge(byte[] key, int offset, int size, Supplier<Result> supplier, Consumer<Result> merge) {
Pair result = getPair(key, offset, size);
Result value = result.slotValue();
if (value == null) {
int slot = result.slot();
slots[slot] = supplier.get();
byte[] bytes = new byte[size];
System.arraycopy(key, offset, bytes, 0, size);
keys[slot] = bytes;
} else {
merge.accept(value);
public static final int MAPSIZE = 1024 * 128;
Result[] slots = new Result[MAPSIZE];
byte[][] keys = new byte[MAPSIZE][];

public void putOrMerge(byte[] key, int offset, int size, double temp, int hash) {
int slot = hash & (slots.length - 1);
var slotValue = slots[slot];
// Linear probe for open slot
while (slotValue != null && (keys[slot].length != size || !Arrays.equals(keys[slot], 0, size, key, offset, size))) {
slot = (slot + 1) & (slots.length - 1);
slotValue = slots[slot];
}
Result value = slotValue;
if (value == null) {
slots[slot] = new Result(temp);
byte[] bytes = new byte[size];
System.arraycopy(key, offset, bytes, 0, size);
keys[slot] = bytes;
} else {
value.min = Math.min(value.min, temp);
value.max = Math.max(value.max, temp);
value.sum += temp;
value.count += 1;
}
}
}

// Get all pairs
public List<Entry> getAll() {
List<Entry> result = new ArrayList<>();
for (int i = 0; i < slots.length; i++) {
Result slotValue = slots[i];
if (slotValue != null) {
result.add(new Entry(keys[i], slotValue));
}

// Get all pairs
public List<Entry> getAll() {
List<Entry> result = new ArrayList<>(slots.length);
for (int i = 0; i < slots.length; i++) {
Result slotValue = slots[i];
if (slotValue != null) {
result.add(new Entry(keys[i], slotValue));
}
}
return result;
}
return result;
}
}

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