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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.lang.foreign.Arena;
import java.lang.reflect.Field;
import java.nio.channels.FileChannel;
import java.nio.channels.FileChannel.MapMode;
import java.nio.charset.StandardCharsets;
import java.nio.file.Path;
import java.nio.file.StandardOpenOption;
import java.util.TreeMap;
import sun.misc.Unsafe;
public class CalculateAverage_abeobk {
private static final String FILE = "./measurements.txt";
private static final int BUCKET_SIZE = 1 << 16;
private static final int BUCKET_MASK = BUCKET_SIZE - 1;
private static final int MAX_STR_LEN = 100;
private static final Unsafe UNSAFE = initUnsafe();
private static final long[] HASH_MASKS = new long[]{
0x0L,
0xffL,
0xffffL,
0xffffffL,
0xffffffffL,
0xffffffffffL,
0xffffffffffffL,
0xffffffffffffffL,
0xffffffffffffffffL, };
private static Unsafe initUnsafe() {
try {
Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
theUnsafe.setAccessible(true);
return (Unsafe) theUnsafe.get(Unsafe.class);
}
catch (Exception ex) {
throw new RuntimeException();
}
}
// stat
private static class Stat {
private int min;
private int max;
private long sum;
private int count;
Stat(int v) {
sum = min = max = v;
count = 1;
}
void add(int val) {
min = Math.min(val, min);
max = Math.max(val, max);
sum += val;
count++;
}
void merge(Stat other) {
min = Math.min(other.min, min);
max = Math.max(other.max, max);
sum += other.sum;
count += other.count;
}
public String toString() {
return String.format("%.1f/%.1f/%.1f", min * 0.1, sum * 0.1 / count, max * 0.1);
}
}
static class Node {
long addr;
int keylen;
int hash;
long[] buf = new long[13];
Stat stat;
String key() {
byte[] buf = new byte[MAX_STR_LEN];
UNSAFE.copyMemory(null, addr, buf, Unsafe.ARRAY_BYTE_BASE_OFFSET, keylen);
return new String(buf, 0, keylen, StandardCharsets.UTF_8);
}
Node(long a, int kl, int h, int v, long[] b) {
stat = new Stat(v);
addr = a;
keylen = kl;
hash = h;
System.arraycopy(b, 0, buf, 0, Math.ceilDiv(kl, 8));
}
boolean contentEquals(final long[] other_buf) {
int k = keylen / 8;
int r = keylen % 8;
// Since the city name is most likely shorter than 16 characters
// this should be faster than typical conditional checks
long sum = 0;
for (int i = 0; i < k; i++) {
sum += buf[i] ^ other_buf[i];
}
sum += (buf[k] ^ other_buf[k]) & HASH_MASKS[r];
return sum == 0;
}
}
// split into chunks
static long[] slice(long start_addr, long end_addr, long chunk_size, int cpu_cnt) {
long[] ptrs = new long[cpu_cnt + 1];
ptrs[0] = start_addr;
for (int i = 1; i < cpu_cnt; i++) {
long addr = start_addr + i * chunk_size;
while (addr < end_addr && UNSAFE.getByte(addr++) != '\n')
;
ptrs[i] = Math.min(addr, end_addr);
}
ptrs[cpu_cnt] = end_addr;
return ptrs;
}
public static void main(String[] args) throws InterruptedException, IOException {
int cpu_cnt = Runtime.getRuntime().availableProcessors() / 2;
try (var file = FileChannel.open(Path.of(FILE), StandardOpenOption.READ)) {
long start_addr = file.map(MapMode.READ_ONLY, 0, file.size(), Arena.global()).address();
long file_size = file.size();
long end_addr = start_addr + file_size;
long chunk_size = Math.ceilDiv(file_size, cpu_cnt);
// processing
var threads = new Thread[cpu_cnt];
var maps = new Node[cpu_cnt][];
var ptrs = slice(start_addr, end_addr, chunk_size, cpu_cnt);
for (int i = 0; i < cpu_cnt; i++) {
int thread_id = i;
long start = ptrs[i];
long end = ptrs[i + 1];
maps[i] = new Node[BUCKET_SIZE + 16]; // extra space for collisions
(threads[i] = new Thread(() -> {
long addr = start;
var map = maps[thread_id];
long[] buf = new long[13];
// parse loop
while (addr < end) {
int idx = 0;
long hash = 0;
long word = 0;
long row_addr = addr;
int semi_pos = 8;
while (semi_pos == 8) {
word = UNSAFE.getLong(addr);
buf[idx++] = word;
// idea from thomaswue & royvanrijn
long xor_semi = word ^ 0x3b3b3b3b3b3b3b3bL; // xor with ;;;;;;;;
long semipos_code = (xor_semi - 0x0101010101010101L) & ~xor_semi & 0x8080808080808080L;
semi_pos = Long.numberOfTrailingZeros(semipos_code) >>> 3;
addr += semi_pos;
hash ^= word & HASH_MASKS[semi_pos];
}
int hash32 = (int) (hash ^ (hash >>> 31));
int keylen = (int) (addr - row_addr);
// great idea from merykitty (Quan Anh Mai)
long num_word = UNSAFE.getLong(++addr);
int dot_pos = Long.numberOfTrailingZeros(~num_word & 0x10101000);
addr += (dot_pos >>> 3) + 3;
int shift = 28 - dot_pos;
long signed = (~num_word << 59) >> 63;
long dsmask = ~(signed & 0xFF);
long digits = ((num_word & dsmask) << shift) & 0x0F000F0F00L;
long abs_val = ((digits * 0x640a0001) >>> 32) & 0x3FF;
int val = (int) ((abs_val ^ signed) - signed);
int bucket = (hash32 & BUCKET_MASK);
while (true) {
var node = map[bucket];
if (node == null) {
map[bucket] = new Node(row_addr, keylen, hash32, val, buf);
break;
}
if (node.keylen == keylen && node.hash == hash32 && node.contentEquals(buf)) {
node.stat.add(val);
break;
}
bucket++;
}
}
})).start();
}
// join all
for (var thread : threads)
thread.join();
// collect results
TreeMap<String, Stat> ms = new TreeMap<>();
for (var map : maps) {
for (var node : map) {
if (node == null)
continue;
var stat = ms.putIfAbsent(node.key(), node.stat);
if (stat != null)
stat.merge(node.stat);
}
}
System.out.println(ms);
}
}
}
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