CalculateAverage_gonix initial attempt (#413)

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gonix 2024-01-16 23:49:39 +02:00 committed by GitHub
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calculate_average_gonix.sh Executable file
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#!/bin/sh
#
# Copyright 2023 The original authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
JAVA_OPTS="--enable-preview"
java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_gonix

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/*
* Copyright 2023 The original authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package dev.morling.onebrc;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.TreeMap;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class CalculateAverage_gonix {
private static final String FILE = "./measurements.txt";
public static void main(String[] args) throws IOException {
var file = new RandomAccessFile(FILE, "r");
var res = buildChunks(file).stream().parallel()
.flatMap(chunk -> new Aggregator().processChunk(chunk).stream())
.collect(Collectors.toMap(
Aggregator.Entry::getKey,
Aggregator.Entry::getValue,
Aggregator.Entry::add,
TreeMap::new));
System.out.println(res);
}
private static List<MappedByteBuffer> buildChunks(RandomAccessFile file) throws IOException {
var fileSize = file.length();
var chunkSize = Math.min(Integer.MAX_VALUE - 512, fileSize / Runtime.getRuntime().availableProcessors());
if (chunkSize <= 0) {
chunkSize = fileSize;
}
var chunks = new ArrayList<MappedByteBuffer>((int) (fileSize / chunkSize) + 1);
var start = 0L;
while (start < fileSize) {
var pos = start + chunkSize;
if (pos < fileSize) {
file.seek(pos);
while (file.read() != '\n') {
pos += 1;
}
pos += 1;
}
else {
pos = fileSize;
}
var buf = file.getChannel().map(FileChannel.MapMode.READ_ONLY, start, pos - start);
buf.order(ByteOrder.nativeOrder());
chunks.add(buf);
start = pos;
}
return chunks;
}
}
class Aggregator {
private static final int MAX_STATIONS = 10_000;
private static final int MAX_STATION_SIZE = (100 * 4) / 8 + 5;
private static final int INDEX_SIZE = 1024 * 1024;
private static final int INDEX_MASK = INDEX_SIZE - 1;
private static final int FLD_MAX = 0;
private static final int FLD_MIN = 1;
private static final int FLD_SUM = 2;
private static final int FLD_COUNT = 3;
// Poor man's hash map: hash code to offset in `mem`.
private final int[] index;
// Contiguous storage of key (station name) and stats fields of all
// unique stations.
// The idea here is to improve locality so that stats fields would
// possibly be already in the CPU cache after we are done comparing
// the key.
private final long[] mem;
private int memUsed;
Aggregator() {
assert ((INDEX_SIZE & (INDEX_SIZE - 1)) == 0) : "INDEX_SIZE must be power of 2";
assert (INDEX_SIZE > MAX_STATIONS) : "INDEX_SIZE must be greater than MAX_STATIONS";
index = new int[INDEX_SIZE];
mem = new long[1 + (MAX_STATIONS * MAX_STATION_SIZE)];
memUsed = 1;
}
Aggregator processChunk(MappedByteBuffer buf) {
// To avoid checking if it is safe to read a whole long near the
// end of a chunk, we copy last couple of lines to a padded buffer
// and process that part separately.
int limit = buf.limit();
int pos = Math.max(limit - 16, -1);
while (pos >= 0 && buf.get(pos) != '\n') {
pos--;
}
pos++;
if (pos > 0) {
processChunkLongs(buf, pos);
}
int tailLen = limit - pos;
var tailBuf = ByteBuffer.allocate(tailLen + 8).order(ByteOrder.nativeOrder());
buf.get(pos, tailBuf.array(), 0, tailLen);
processChunkLongs(tailBuf, tailLen);
return this;
}
Aggregator processChunkLongs(ByteBuffer buf, int limit) {
int pos = 0;
while (pos < limit) {
int start = pos;
int hash = 0;
while (true) {
// This is a bit ugly, but it is faster than reading by byte.
long tmpLong = buf.getLong(pos);
if ((tmpLong & 0xFF) == ';') {
break;
}
if (((tmpLong >>> 8) & 0xFF) == ';') {
hash = (33 * hash) ^ (int) (tmpLong & 0xFF);
pos += 1;
break;
}
if (((tmpLong >>> 16) & 0xFF) == ';') {
hash = (33 * hash) ^ (int) (tmpLong & 0xFFFF);
pos += 2;
break;
}
if (((tmpLong >>> 24) & 0xFF) == ';') {
hash = (33 * hash) ^ (int) (tmpLong & 0xFFFFFF);
pos += 3;
break;
}
if (((tmpLong >>> 32) & 0xFF) == ';') {
hash = (33 * hash) ^ (int) (tmpLong & 0xFFFFFFFF);
pos += 4;
break;
}
if (((tmpLong >>> 40) & 0xFF) == ';') {
hash = ((33 * hash) ^ (int) (tmpLong & 0xFFFFFFFF)) + (int) ((tmpLong >>> 33) & 0xFF);
pos += 5;
break;
}
if (((tmpLong >>> 48) & 0xFF) == ';') {
hash = ((33 * hash) ^ (int) (tmpLong & 0xFFFFFFFF)) + (int) ((tmpLong >>> 33) & 0xFFFF);
pos += 6;
break;
}
if (((tmpLong >>> 56) & 0xFF) == ';') {
hash = ((33 * hash) ^ (int) (tmpLong & 0xFFFFFFFF)) + (int) ((tmpLong >>> 33) & 0xFFFFFF);
pos += 7;
break;
}
hash = ((33 * hash) ^ (int) (tmpLong & 0xFFFFFFFF)) + (int) ((tmpLong >>> 33) & 0xFFFFFFFF);
pos += 8;
}
hash = (33 * hash) ^ (hash >>> 15);
int len = pos - start;
assert (buf.get(pos) == ';') : "Expected ';'";
pos++;
int measurement;
{
long tmpLong = buf.getLong(pos);
int sign = 1;
if ((tmpLong & 0xFF) == '-') {
sign = -1;
tmpLong >>>= 8;
pos++;
}
int value;
if (((tmpLong >>> 8) & 0xFF) == '.') {
value = (int) (((tmpLong & 0xFF) - '0') * 10 + (((tmpLong >>> 16) & 0xFF) - '0'));
pos += 4;
}
else {
value = (int) (((tmpLong & 0xFF) - '0') * 100 + (((tmpLong >>> 8) & 0xFF) - '0') * 10 + (((tmpLong >>> 24) & 0xFF) - '0'));
pos += 5;
}
measurement = sign * value;
}
assert (buf.get(pos - 1) == '\n') : "Expected '\\n'";
add(buf, start, len, hash, measurement);
}
return this;
}
public Stream<Entry> stream() {
return Arrays.stream(index)
.filter(offset -> offset != 0)
.mapToObj(offset -> new Entry(mem, offset));
}
private void add(ByteBuffer buf, int start, int len, int hash, int measurement) {
int idx = hash & INDEX_MASK;
while (true) {
if (index[idx] != 0) {
int offset = index[idx];
if (keyEqual(offset, buf, start, len)) {
int pos = offset + (len >> 3) + 2;
mem[pos + FLD_MIN] = Math.min((int) measurement, (int) mem[pos + FLD_MIN]);
mem[pos + FLD_MAX] = Math.max((int) measurement, (int) mem[pos + FLD_MAX]);
mem[pos + FLD_SUM] += measurement;
mem[pos + FLD_COUNT] += 1;
return;
}
}
else {
index[idx] = create(buf, start, len, hash, measurement);
return;
}
idx = (idx + 1) & INDEX_MASK;
}
}
private int create(ByteBuffer buf, int start, int len, int hash, int measurement) {
int offset = memUsed;
mem[offset] = len;
int memPos = offset + 1;
int memEndEarly = memPos + (len >> 3);
int bufPos = start;
int bufEnd = start + len;
while (memPos < memEndEarly) {
mem[memPos] = buf.getLong(bufPos);
memPos += 1;
bufPos += 8;
}
if (bufPos < bufEnd) {
int shift = (8 - (len & 7)) << 3; // (8 - (len % 8)) * 8
long tmpLong = buf.getLong(bufPos) << shift >>> shift;
mem[memPos] = tmpLong;
}
else {
// "consume" extra long - makes math a bit simpler to calculate
// fields offset for update.
mem[memPos] = 0;
}
memPos += 1;
mem[memPos + FLD_MIN] = measurement;
mem[memPos + FLD_MAX] = measurement;
mem[memPos + FLD_SUM] = measurement;
mem[memPos + FLD_COUNT] = 1;
memUsed = memPos + 4;
return offset;
}
private boolean keyEqual(int offset, ByteBuffer buf, int start, int len) {
if (len != mem[offset]) {
return false;
}
int memPos = offset + 1;
int memEndEarly = memPos + (len >> 3);
int bufPos = start;
int bufEnd = start + len;
while (memPos < memEndEarly) {
if (mem[memPos] != buf.getLong(bufPos)) {
return false;
}
memPos += 1;
bufPos += 8;
}
if (bufPos < bufEnd) {
int shift = (8 - (len & 7)) << 3; // (8 - (len % 8)) * 8
long tmpLong = buf.getLong(bufPos) << shift >>> shift;
if (mem[memPos] != tmpLong) {
return false;
}
}
return true;
}
public static class Entry {
private final long[] mem;
private final int offset;
private String key;
Entry(long[] mem, int offset) {
this.mem = mem;
this.offset = offset;
}
public String getKey() {
if (key == null) {
int pos = this.offset;
int keyLen = (int) mem[pos++];
var tmpBuf = ByteBuffer.allocate(keyLen + 8).order(ByteOrder.nativeOrder());
for (int i = 0; i < keyLen; i += 8) {
tmpBuf.putLong(mem[pos++]);
}
key = new String(tmpBuf.array(), 0, keyLen, StandardCharsets.UTF_8);
}
return key;
}
public Entry add(Entry other) {
int keyLen = (int) mem[offset];
int fldOffset = (keyLen >> 3) + 2;
int pos = offset + fldOffset;
int otherPos = other.offset + fldOffset;
long[] otherMem = other.mem;
mem[pos + FLD_MIN] = Math.min((int) mem[pos + FLD_MIN], (int) otherMem[otherPos + FLD_MIN]);
mem[pos + FLD_MAX] = Math.max((int) mem[pos + FLD_MAX], (int) otherMem[otherPos + FLD_MAX]);
mem[pos + FLD_SUM] += otherMem[otherPos + FLD_SUM];
mem[pos + FLD_COUNT] += otherMem[otherPos + FLD_COUNT];
return this;
}
public Entry getValue() {
return this;
}
@Override
public String toString() {
int keyLen = (int) mem[offset];
int pos = offset + (keyLen >> 3) + 2;
return round(mem[pos + FLD_MIN])
+ "/" + round(((double) mem[pos + FLD_SUM]) / mem[pos + FLD_COUNT])
+ "/" + round(mem[pos + FLD_MAX]);
}
private static double round(double value) {
return Math.round(value) / 10.0;
}
}
}