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-rw-r--r--src/main/java/dev/morling/onebrc/CalculateAverage_karthikeyan97.java209
1 files changed, 102 insertions, 107 deletions
diff --git a/src/main/java/dev/morling/onebrc/CalculateAverage_karthikeyan97.java b/src/main/java/dev/morling/onebrc/CalculateAverage_karthikeyan97.java
index c17e927..7014b12 100644
--- a/src/main/java/dev/morling/onebrc/CalculateAverage_karthikeyan97.java
+++ b/src/main/java/dev/morling/onebrc/CalculateAverage_karthikeyan97.java
@@ -22,9 +22,12 @@ import static java.util.stream.Collectors.*;
import java.io.FileInputStream;
import java.io.RandomAccessFile;
+import java.lang.foreign.Arena;
import java.lang.reflect.Field;
import java.nio.ByteBuffer;
+import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
+import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
@@ -33,6 +36,7 @@ import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
+import java.util.Scanner;
import java.util.Set;
import java.util.TreeMap;
import java.util.function.BiConsumer;
@@ -44,8 +48,21 @@ import java.util.stream.Collectors;
public class CalculateAverage_karthikeyan97 {
+ private static final Unsafe UNSAFE = initUnsafe();
+
private static final String FILE = "./measurements.txt";
+ private static Unsafe initUnsafe() {
+ try {
+ Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
+ theUnsafe.setAccessible(true);
+ return (Unsafe) theUnsafe.get(Unsafe.class);
+ }
+ catch (NoSuchFieldException | IllegalAccessException e) {
+ throw new RuntimeException(e);
+ }
+ }
+
private record Measurement(modifiedbytearray station, double value) {
}
@@ -53,18 +70,18 @@ public class CalculateAverage_karthikeyan97 {
}
private static class MeasurementAggregator {
- private double min = Double.POSITIVE_INFINITY;
- private double max = Double.NEGATIVE_INFINITY;
+ private long min = Long.MAX_VALUE;
+ private long max = Long.MIN_VALUE;
private long sum;
private long count;
public String toString() {
return new StringBuffer(14)
- .append(round(min))
+ .append(round((1.0 * min)))
.append("/")
.append(round((1.0 * sum) / count))
.append("/")
- .append(round(max)).toString();
+ .append(round((1.0 * max))).toString();
}
private double round(double value) {
@@ -74,7 +91,7 @@ public class CalculateAverage_karthikeyan97 {
public static void main(String[] args) throws Exception {
// long start = System.nanoTime();
- System.setSecurityManager(null);
+ // System.setSecurityManager(null);
Collector<Map.Entry<modifiedbytearray, MeasurementAggregator>, MeasurementAggregator, MeasurementAggregator> collector = Collector.of(
MeasurementAggregator::new,
(a, m) -> {
@@ -103,15 +120,17 @@ public class CalculateAverage_karthikeyan97 {
},
agg -> agg);
- RandomAccessFile raf = new RandomAccessFile(FILE, "rw");
+ RandomAccessFile raf = new RandomAccessFile(FILE, "r");
+ FileChannel fileChannel = raf.getChannel();
+ final long mappedAddress = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, raf.length(), Arena.global()).address();
long length = raf.length();
- int cores = length > 1000 ? Runtime.getRuntime().availableProcessors() : 1;
+ final long endAddress = mappedAddress + length - 1;
+ int cores = length > 1000 ? Runtime.getRuntime().availableProcessors() * 2 : 1;
long boundary[][] = new long[cores][2];
long segments = length / (cores);
long before = -1;
for (int i = 0; i < cores - 1; i++) {
boundary[i][0] = before + 1;
- byte[] b = new byte[107];
if (before + segments - 107 > 0) {
raf.seek(before + segments - 107);
}
@@ -130,120 +149,92 @@ public class CalculateAverage_karthikeyan97 {
f.setAccessible(true);
Unsafe unsafe = (Unsafe) f.get(null);
- int pageSize = unsafe.pageSize() * 10;
+ int l3Size = (13 * 1024 * 1024);// unsafe.l3Size();
System.out.println(new TreeMap((Arrays.stream(boundary).parallel().map(i -> {
FileInputStream fileInputStream = null;
try {
- fileInputStream = new FileInputStream(FILE);
- FileChannel fileChannel = fileInputStream.getChannel();
- HashMap<modifiedbytearray, MeasurementAggregator> resultmap = new HashMap<>(12000, 100);
-
- ByteBuffer buffer = ByteBuffer.allocateDirect(pageSize);
-
- fileChannel.position(i[0]);
- int bytesReading = 0;
- double num = 0;
+ int seglen = (int) (i[1] - i[0] + 1);
+ HashMap<modifiedbytearray, MeasurementAggregator> resultmap = new HashMap<>(1000);
+ long segstart = mappedAddress + i[0];
+ int bytesRemaining = seglen;
+ long num = 0;
int sign = 1;
boolean isNumber = false;
byte bi;
modifiedbytearray stationName = null;
- int hascode = 1;
- int ctr = 0;
- byte[] arr = new byte[100];
- int arrptr = 0;
- int seglen = (int) (i[1] - i[0] + 1);
- while (bytesReading < seglen) {
- buffer.clear();
- int bytesRead = fileChannel.read(buffer);
- if ((bytesReading + bytesRead) <= seglen) {
- if (bytesRead < 0) {
- bytesRead = 0;
- }
- }
- else {
- bytesRead = (seglen - bytesReading);
- }
- buffer.flip();
+ int hascode = 5381;
+ while (bytesRemaining > 0) {
int bytesptr = 0;
- byte[] bufferArr = new byte[bytesRead];
- buffer.get(bufferArr);
- while (bytesptr < bytesRead) {
- bytesReading += 1;
- bi = bufferArr[bytesptr++];
- if (ctr > 0) {
- arr[arrptr++] = bi;
- hascode = 31 * hascode + bi;
- ctr--;
- }
- else {
- if (bi >= 240) {
- arr[arrptr++] = bi;
- hascode = 31 * hascode + bi;
- ctr = 3;
- }
- else if (bi >= 224) {
- arr[arrptr++] = bi;
- hascode = 31 * hascode + bi;
- ctr = 2;
- }
- else if (bi >= 192) {
- arr[arrptr++] = bi;
- hascode = 31 * hascode + bi;
- ctr = 1;
+ // int bytesread = buffer.remaining() > l3Size ? l3Size : buffer.remaining();
+ // byte[] bufferArr = new byte[bytesread];
+ // buffer.get(bufferArr);
+ int bbstart = 0;
+ int readSize = bytesRemaining > l3Size ? l3Size : bytesRemaining;
+ int actualReadSize = (segstart + readSize + 110 > endAddress || readSize + 110 > i[1]) ? readSize : readSize + 110;
+ byte[] readArr = new byte[actualReadSize];
+
+ UNSAFE.copyMemory(null, segstart, readArr, UNSAFE.ARRAY_BYTE_BASE_OFFSET, actualReadSize);
+ while (bytesptr < actualReadSize) {
+ bi = readArr[bytesptr++];// UNSAFE.getByte(segstart + bytesReading++);
+ if (!isNumber) {
+ if (bi >= 192) {
+ hascode = (hascode << 5) + hascode ^ bi;
}
else if (bi == 59) {
isNumber = true;
- stationName = new modifiedbytearray(arr, arrptr, hascode);
- arr = new byte[100];
- arrptr = 0;
- hascode = 1;
- }
- else if (bi == 10) {
- hascode = 1;
- isNumber = false;
- MeasurementAggregator agg = resultmap.get(stationName);
- num *= sign;
- if (agg == null) {
- agg = new MeasurementAggregator();
- agg.min = num;
- agg.max = num;
- agg.sum = (long) (num);
- agg.count = 1;
- resultmap.put(stationName, agg);
+ stationName = new modifiedbytearray(readArr, bbstart, bytesptr - 2, hascode & 0xFFFFFFFF);
+ bbstart = 0;
+ hascode = 5381;
+ if (bytesptr >= readSize) {
+ break;
}
- else {
- if (agg.min >= num) {
+ }
+ else {
+ hascode = (hascode << 5) + hascode ^ bi;
+ }
+ }
+ else {
+ switch (bi) {
+ case 0x2E:
+ break;
+ case 0x2D:
+ sign = -1;
+ break;
+ case 10:
+ hascode = 5381;
+ isNumber = false;
+ bbstart = bytesptr;
+ MeasurementAggregator agg = resultmap.get(stationName);
+ num *= sign;
+ if (agg == null) {
+ agg = new MeasurementAggregator();
agg.min = num;
- }
- if (agg.max <= num) {
agg.max = num;
+ agg.sum = (long) (num);
+ agg.count = 1;
+ resultmap.put(stationName, agg);
}
- agg.sum += (long) (num);
- agg.count++;
- }
- num = 0;
- sign = 1;
- }
- else {
- hascode = 31 * hascode + bi;
- if (isNumber) {
- switch (bi) {
- case 0x2E:
- break;
- case 0x2D:
- sign = -1;
- break;
- default:
- num = num * 10 + (bi - 0x30);
+ else {
+ if (agg.min >= num) {
+ agg.min = num;
+ }
+ if (agg.max <= num) {
+ agg.max = num;
+ }
+ agg.sum += (long) (num);
+ agg.count++;
}
- }
- else {
- arr[arrptr++] = bi;
- }
+ num = 0;
+ sign = 1;
+ break;
+ default:
+ num = num * 10 + (bi - 0x30);
}
}
}
+ bytesRemaining -= bytesptr;
+ segstart += bytesptr;
}
/*
* while (bytesReading < (i[1] - i[0] + 1) && buffer.position() < buffer.limit()) {
@@ -335,7 +326,7 @@ public class CalculateAverage_karthikeyan97 {
*/
// Get the FileChannel from the FileInputStream
- // System.out.println("time taken:" + (System.nanoTime() - start) / 1000000);
+ // System.out.println("time taken1:" + (System.nanoTime() - start) / 1000000);
// System.out.println(measurements);
}
@@ -343,17 +334,21 @@ public class CalculateAverage_karthikeyan97 {
class modifiedbytearray {
private int length;
+ private int start;
+ private int end;
private byte[] arr;
public int hashcode;
- modifiedbytearray(byte[] arr, int length, int hashcode) {
+ modifiedbytearray(byte[] arr, int start, int end, int hashcode) {
this.arr = arr;
- this.length = length;
+ this.length = end - start + 1;
+ this.end = end;
+ this.start = start;
this.hashcode = hashcode;
}
public String getStationName() {
- return new String(this.getArr(), 0, length, StandardCharsets.UTF_8);
+ return new String(this.getArr(), start, length, StandardCharsets.UTF_8);
}
public byte[] getArr() {
@@ -368,7 +363,7 @@ class modifiedbytearray {
@Override
public boolean equals(Object obj) {
modifiedbytearray b = (modifiedbytearray) obj;
- return Arrays.equals(this.getArr(), 0, length, b.arr, 0, b.length);
+ return Arrays.equals(this.getArr(), start, end, b.arr, b.start, b.end);
}
public int getHashcode() {
generated by cgit v1.2.3 (git 2.25.1) at 2026-05-13 10:15:07 +0000