Playground/1brc
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Down to 14s locally (#583)

Browse Source 
Use flat array for stats.
Use simd for line termination

Co-authored-by: Ian Preston <ianopolous@protonmail.com>
This commit is contained in:
Dr Ian Preston 2024-01-25 22:03:05 +00:00 committed by GitHub
parent d5cedd6a35
commit 0bd1675571
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
1 changed files with 70 additions and 50 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

118
src/main/java/dev/morling/onebrc/CalculateAverage_ianopolousfast.java
View File

@ -41,7 +41,7 @@ import static java.lang.foreign.ValueLayout.*;
*
* Timings on 4 core i7-7500U CPU @ 2.70GHz:
* average_baseline: 4m48s
* ianopolous: 15s
* ianopolous: 14s
*/
public class CalculateAverage_ianopolousfast {
@ -60,7 +60,7 @@ public class CalculateAverage_ianopolousfast {
MemorySegment mmap = channel.map(FileChannel.MapMode.READ_ONLY, 0, filesize, arena);
int nChunks = filesize < 4 * 1024 * 1024 ? 1 : Runtime.getRuntime().availableProcessors();
long chunkSize = (filesize + nChunks - 1) / nChunks;
List<List<List<Stat>>> allResults = IntStream.range(0, nChunks)
List<Stat[]> allResults = IntStream.range(0, nChunks)
.parallel()
.mapToObj(i -> parseStats(i * chunkSize, Math.min((i + 1) * chunkSize, filesize), mmap))
.toList();
@ -69,7 +69,7 @@ public class CalculateAverage_ianopolousfast {
.parallel()
.flatMap(f -> {
try {
return f.stream().filter(Objects::nonNull).flatMap(Collection::stream);
return Arrays.stream(f).filter(Objects::nonNull);
}
catch (Exception e) {
e.printStackTrace();
@ -104,24 +104,23 @@ public class CalculateAverage_ianopolousfast {
return new Stat(stationBuffer);
}
public static Stat dedupeStation(long start, long end, long hash, MemorySegment buffer, List<List<Stat>> stations) {
public static Stat dedupeStation(long start, long end, long hash, MemorySegment buffer, Stat[] stations) {
int index = hashToIndex(hash, MAX_STATIONS);
List<Stat> matches = stations.get(index);
if (matches == null) {
List<Stat> value = new ArrayList<>();
Stat match = stations[index];
if (match == null) {
Stat res = createStation(start, end, buffer);
value.add(res);
stations.set(index, value);
stations[index] = res;
return res;
}
else {
for (int i = 0; i < matches.size(); i++) {
Stat s = matches.get(i);
if (matchingStationBytes(start, end, buffer, s))
return s;
while (match != null) {
if (matchingStationBytes(start, end, buffer, match))
return match;
index = (index + 1) % stations.length;
match = stations[index];
}
Stat res = createStation(start, end, buffer);
matches.add(res);
stations[index] = res;
return res;
}
}
@ -130,50 +129,38 @@ public class CalculateAverage_ianopolousfast {
return d & (-1L << ((8 - nbytes) * 8));
}
public static Stat parseStation(long lineStart, MemorySegment buffer, List<List<Stat>> stations) {
public static Stat parseStation(long lineStart, MemorySegment buffer, Stat[] stations) {
ByteVector line = ByteVector.fromMemorySegment(BYTE_SPECIES, buffer, lineStart, ByteOrder.nativeOrder());
int keySize = line.compare(VectorOperators.EQ, ';').firstTrue();
long first8 = buffer.get(LONG_LAYOUT, lineStart);
if (keySize == BYTE_SPECIES.vectorByteSize()) {
while (buffer.get(JAVA_BYTE, lineStart + keySize) != ';') {
keySize++;
}
long second8 = buffer.get(LONG_LAYOUT, lineStart + 8);
long hash = first8 ^ second8; // todo include other bytes
return dedupeStation(lineStart, lineStart + keySize, hash, buffer, stations);
}
long second8 = 0;
if (keySize <= 8) {
first8 = maskHighBytes(first8, keySize & 0x07);
}
long second8 = keySize <= 8 ? 0 : maskHighBytes(buffer.get(LONG_LAYOUT, lineStart + 8), keySize & 0x07);
else if (keySize <= 16) {
second8 = maskHighBytes(buffer.get(LONG_LAYOUT, lineStart + 8), keySize & 0x07);
}
else if (keySize == BYTE_SPECIES.vectorByteSize()) {
while (buffer.get(JAVA_BYTE, lineStart + keySize) != ';') {
keySize++;
}
second8 = maskHighBytes(buffer.get(LONG_LAYOUT, lineStart + 8), keySize & 0x07);
}
long hash = first8 ^ second8; // todo include later bytes
return dedupeStation(lineStart, lineStart + keySize, hash, buffer, stations);
}
public static int getDot(long d) {
// from Hacker's Delight page 92
d = d ^ 0x2e2e2e2e2e2e2e2eL;
long y = (d & 0x7f7f7f7f7f7f7f7fL) + 0x7f7f7f7f7f7f7f7fL;
y = ~(y | d | 0x7f7f7f7f7f7f7f7fL);
return Long.numberOfLeadingZeros(y) >> 3;
}
public static short getMinus(long d) {
d = d & 0xff00000000000000L;
d = d ^ 0x2d2d2d2d2d2d2d2dL;
long y = (d & 0x7f7f7f7f7f7f7f7fL) + 0x7f7f7f7f7f7f7f7fL;
y = ~(y | d | 0x7f7f7f7f7f7f7f7fL);
return (short) ((Long.numberOfLeadingZeros(y) >> 6) - 1);
return ((d & 0xff00000000000000L) ^ 0x2d00000000000000L) != 0 ? 0 : (short) -1;
}
public static long processTemperature(long lineSplit, MemorySegment buffer, Stat station) {
public static long processTemperature(long lineSplit, int size, MemorySegment buffer, Stat station) {
long d = buffer.get(LONG_LAYOUT, lineSplit);
// negative is either 0 or -1
short negative = getMinus(d);
d = d << (negative * -8);
int dotIndex = getDot(d);
int dotIndex = size - 2 + negative;
d = (d >> 8) | 0x30000000_00000000L; // add a leading 0 digit
d = d >> 8 * (5 - dotIndex);
short temperature = (short) ((byte) d - '0' +
@ -181,10 +168,41 @@ public class CalculateAverage_ianopolousfast {
100 * (((byte) (d >> 24)) - '0'));
temperature = (short) ((temperature ^ negative) - negative); // negative treatment inspired by merkitty
station.add(temperature);
return lineSplit - negative + dotIndex + 3;
return lineSplit + size + 1;
}
public static List<List<Stat>> parseStats(long startByte, long endByte, MemorySegment buffer) {
private static long parseLine(long lineStart, MemorySegment buffer, Stat[] stations) {
ByteVector line = ByteVector.fromMemorySegment(BYTE_SPECIES, buffer, lineStart, ByteOrder.nativeOrder());
int lineSize = line.compare(VectorOperators.EQ, '\n').firstTrue();
int index = lineSize;
while (index == BYTE_SPECIES.vectorByteSize()) {
index = ByteVector.fromMemorySegment(BYTE_SPECIES, buffer, lineStart + lineSize,
ByteOrder.nativeOrder()).compare(VectorOperators.EQ, '\n').firstTrue();
lineSize += index;
}
int keySize = lineSize - 6 + ByteVector.fromMemorySegment(BYTE_SPECIES, buffer, lineStart + lineSize - 6,
ByteOrder.nativeOrder()).compare(VectorOperators.EQ, ';').firstTrue();
long first8 = buffer.get(LONG_LAYOUT, lineStart);
long second8 = 0;
if (keySize <= 8) {
first8 = maskHighBytes(first8, keySize & 0x07);
}
else if (keySize <= 16) {
second8 = maskHighBytes(buffer.get(LONG_LAYOUT, lineStart + 8), keySize & 0x07);
}
else if (keySize == BYTE_SPECIES.vectorByteSize()) {
while (buffer.get(JAVA_BYTE, lineStart + keySize) != ';') {
keySize++;
}
second8 = maskHighBytes(buffer.get(LONG_LAYOUT, lineStart + 8), keySize & 0x07);
}
long hash = first8 ^ second8; // todo include later bytes
Stat station = dedupeStation(lineStart, lineStart + keySize, hash, buffer, stations);
return processTemperature(lineStart + keySize + 1, lineSize - keySize - 1, buffer, station);
}
public static Stat[] parseStats(long startByte, long endByte, MemorySegment buffer) {
// read first partial line
if (startByte > 0) {
for (int i = 0; i < MAX_LINE_LENGTH; i++) {
@ -195,9 +213,7 @@ public class CalculateAverage_ianopolousfast {
}
}
List<List<Stat>> stations = new ArrayList<>(MAX_STATIONS);
for (int i = 0; i < MAX_STATIONS; i++)
stations.add(null);
Stat[] stations = new Stat[MAX_STATIONS];
// Handle reading the very last few lines in the file
// this allows us to not worry about reading beyond the end
@ -218,7 +234,12 @@ public class CalculateAverage_ianopolousfast {
int index = 0;
while (endByte + index < buffer.byteSize()) {
Stat station = parseStation(index, end, stations);
index = (int) processTemperature(index + station.namelen + 1, end, station);
int tempSize = 3;
if (end.get(JAVA_BYTE, index + station.namelen + 5) == '\n')
tempSize = 4;
if (end.get(JAVA_BYTE, index + station.namelen + 6) == '\n')
tempSize = 5;
index = (int) processTemperature(index + station.namelen + 1, tempSize, end, station);
}
}
@ -226,10 +247,9 @@ public class CalculateAverage_ianopolousfast {
return stations;
}
private static void innerloop(long startByte, long endByte, MemorySegment buffer, List<List<Stat>> stations) {
private static void innerloop(long startByte, long endByte, MemorySegment buffer, Stat[] stations) {
while (startByte < endByte) {
Stat station = parseStation(startByte, buffer, stations);
startByte = processTemperature(startByte + station.namelen + 1, buffer, station);
startByte = parseLine(startByte, buffer, stations);
}
}