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ddimtirov - switched to the foreign memory access preview API for another 10% speedup

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Dimitar Dimitrov 2024-01-04 04:22:39 +09:00 committed by Gunnar Morling
parent 1923fc65a8
commit d73457872f
2 changed files with 69 additions and 60 deletions
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5
calculate_average_ddimtirov.sh
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@ -15,6 +15,7 @@
# limitations under the License.
#
JAVA_OPTS="-XX:+UseParallelGC"
# --enable-preview to use the new memory mapped segments
# We don't allocate much, so just give it 1G heap and turn off GC; the AlwaysPreTouch was suggested by the ergonomics
JAVA_OPTS="--enable-preview -Xms1g -Xmx1g -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -XX:+AlwaysPreTouch"
time java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_ddimtirov

124
src/main/java/dev/morling/onebrc/CalculateAverage_ddimtirov.java
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@ -15,9 +15,10 @@
*/
package dev.morling.onebrc;
import java.io.*;
import java.nio.MappedByteBuffer;
import java.lang.foreign.Arena;
import java.lang.foreign.MemorySegment;
import java.lang.foreign.ValueLayout;
import java.nio.channels.FileChannel;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
@ -47,15 +48,16 @@ public class CalculateAverage_ddimtirov {
var start = Instant.now();
var desiredSegmentsCount = Runtime.getRuntime().availableProcessors();
var segments = FileSegment.forFile(path, desiredSegmentsCount);
var fileSegments = FileSegment.forFile(path, desiredSegmentsCount);
var trackers = segments.stream().parallel().map(segment -> {
var trackers = fileSegments.stream().parallel().map(fileSegment -> {
try (var fileChannel = (FileChannel) Files.newByteChannel(path, StandardOpenOption.READ)) {
var tracker = new Tracker();
var segmentBuffer = fileChannel.map(FileChannel.MapMode.READ_ONLY, segment.start(), segment.size());
tracker.processSegment(segmentBuffer, segment.end());
var memorySegment = fileChannel.map(FileChannel.MapMode.READ_ONLY, fileSegment.start(), fileSegment.size(), Arena.ofConfined());
tracker.processSegment(memorySegment);
return tracker;
} catch (IOException e) {
}
catch (IOException e) {
throw new RuntimeException(e);
}
}).toList();
@ -63,27 +65,27 @@ public class CalculateAverage_ddimtirov {
var result = summarizeTrackers(trackers);
System.out.println(result);
//noinspection ConstantValue
if (start!=null) System.err.println(Duration.between(start, Instant.now()));
assert Files.readAllLines(Path.of("expected_result.txt")).getFirst().equals(result);
// noinspection ConstantValue
if (start != null)
System.err.println(Duration.between(start, Instant.now()));
assert Files.readAllLines(Path.of("measurements_result.txt")).getFirst().equals(result);
}
record FileSegment(long start, long end) {
public long size() { return end() - start(); }
record FileSegment(long start, long size) {
public static List<FileSegment> forFile(Path file, int desiredSegmentsCount) throws IOException {
try (var raf = new RandomAccessFile(file.toFile(), "r")) {
List<FileSegment> segments = new ArrayList<>();
long fileSize = raf.length();
long segmentSize = fileSize / desiredSegmentsCount;
var segments = new ArrayList<FileSegment>();
var fileSize = raf.length();
var segmentSize = fileSize / desiredSegmentsCount;
for (int segmentIdx = 0; segmentIdx < desiredSegmentsCount; segmentIdx++) {
long segStart = segmentIdx * segmentSize;
long segEnd = (segmentIdx == desiredSegmentsCount - 1) ? fileSize : segStart + segmentSize;
var segStart = segmentIdx * segmentSize;
var segEnd = (segmentIdx == desiredSegmentsCount - 1) ? fileSize : segStart + segmentSize;
segStart = findSegmentBoundary(raf, segmentIdx, 0, segStart, segEnd);
segEnd = findSegmentBoundary(raf, segmentIdx, desiredSegmentsCount - 1, segEnd, fileSize);
segments.add(new FileSegment(segStart, segEnd));
var segSize = segEnd - segStart;
segments.add(new FileSegment(segStart, segSize));
}
return segments;
}
@ -103,28 +105,33 @@ public class CalculateAverage_ddimtirov {
private static String summarizeTrackers(List<Tracker> trackers) {
var result = new TreeMap<String, String>();
for (int i = 0; i < HASH_NO_CLASH_MODULUS; i++) {
for (var i = 0; i < HASH_NO_CLASH_MODULUS; i++) {
String name = null;
int min = Integer.MAX_VALUE;
int max = Integer.MIN_VALUE;
long sum = 0;
long count = 0;
var min = Integer.MAX_VALUE;
var max = Integer.MIN_VALUE;
var sum = 0L;
var count = 0L;
for (Tracker tracker : trackers) {
if (tracker.names[i]==null) continue;
if (name==null) name = tracker.names[i];
if (tracker.names[i] == null)
continue;
if (name == null)
name = tracker.names[i];
var minn = tracker.minMaxCount[i*3];
var maxx = tracker.minMaxCount[i*3+1];
if (minn<min) min = minn;
if (maxx>max) max = maxx;
count += tracker.minMaxCount[i*3+2];
var minn = tracker.minMaxCount[i * 3];
var maxx = tracker.minMaxCount[i * 3 + 1];
if (minn < min)
min = minn;
if (maxx > max)
max = maxx;
count += tracker.minMaxCount[i * 3 + 2];
sum += tracker.sums[i];
}
if (name==null) continue;
if (name == null)
continue;
var mean = Math.round((double) sum / count) / 10.0;
result.put(name, (min/10.0) + "/" + mean + "/" + (max/10.0));
result.put(name, (min / 10.0) + "/" + mean + "/" + (max / 10.0));
}
return result.toString();
}
@ -133,51 +140,50 @@ public class CalculateAverage_ddimtirov {
private final int[] minMaxCount = new int[HASH_NO_CLASH_MODULUS * 3];
private final long[] sums = new long[HASH_NO_CLASH_MODULUS];
private final String[] names = new String[HASH_NO_CLASH_MODULUS];
private final byte[] nameThreadLocal = new byte[64];
private void processSegment(MappedByteBuffer segmentBuffer, long segmentEnd) {
int startLine;
int limit = segmentBuffer.limit();
while ((startLine = segmentBuffer.position()) < limit) {
int pos = startLine;
private void processSegment(MemorySegment memory) {
int position = 0;
long limit = memory.byteSize();
while (position < limit) {
int pos = position;
byte b;
int nameLength = 0, nameHash = 0;
while (pos != segmentEnd && (b = segmentBuffer.get(pos++)) != ';') {
nameHash = nameHash*31 + b;
while ((b = memory.get(ValueLayout.JAVA_BYTE, pos++)) != ';') {
nameHash = nameHash * 31 + b;
nameLength++;
}
int temperature = 0, sign = 1;
outer:
while (pos != segmentEnd && (b = segmentBuffer.get(pos++)) != '\n') {
outer: while ((b = memory.get(ValueLayout.JAVA_BYTE, pos++)) != '\n') {
switch (b) {
case '\r' :
case '\r':
pos++;
break outer;
case '.' :
case '.':
break;
case '-' :
case '-':
sign = -1;
break;
default :
default:
var digit = b - '0';
assert digit >= 0 && digit <= 9;
temperature = 10 * temperature + digit;
}
}
processLine(nameHash, segmentBuffer, startLine, nameLength, temperature * sign);
segmentBuffer.position(pos);
processLine(nameHash, memory, position, nameLength, temperature * sign);
position = pos;
}
}
public void processLine(int nameHash, MappedByteBuffer buffer, int nameOffset, int nameLength, int temperature) {
public void processLine(int nameHash, MemorySegment buffer, int nameOffset, int nameLength, int temperature) {
var i = Math.abs(nameHash) % HASH_NO_CLASH_MODULUS;
if (names[i]==null) {
if (names[i] == null) {
names[i] = parseName(buffer, nameOffset, nameLength);
} else {
}
else {
assert parseName(buffer, nameOffset, nameLength).equals(names[i]) : parseName(buffer, nameOffset, nameLength) + "!=" + names[i];
}
@ -186,15 +192,17 @@ public class CalculateAverage_ddimtirov {
int mmcIndex = i * 3;
var min = minMaxCount[mmcIndex + OFFSET_MIN];
var max = minMaxCount[mmcIndex + OFFSET_MAX];
if (temperature < min) minMaxCount[mmcIndex + OFFSET_MIN] = temperature;
if (temperature > max) minMaxCount[mmcIndex + OFFSET_MAX] = temperature;
if (temperature < min)
minMaxCount[mmcIndex + OFFSET_MIN] = temperature;
if (temperature > max)
minMaxCount[mmcIndex + OFFSET_MAX] = temperature;
minMaxCount[mmcIndex + OFFSET_COUNT]++;
}
private String parseName(MappedByteBuffer buffer, int nameOffset, int nameLength) {
buffer.get(nameOffset, nameThreadLocal, 0, nameLength);
return new String(nameThreadLocal, 0, nameLength, StandardCharsets.UTF_8);
private String parseName(MemorySegment memory, int nameOffset, int nameLength) {
byte[] array = memory.asSlice(nameOffset, nameLength).toArray(ValueLayout.JAVA_BYTE);
return new String(array, StandardCharsets.UTF_8);
}
}
}