8247605: Avoid array allocation when concatenating with empty string

Reviewed-by: redestad, plevart
This commit is contained in:
Tagir F. Valeev 2020-08-10 16:14:03 +00:00
parent 8e687450d6
commit 55e381b32f
5 changed files with 304 additions and 238 deletions

View file

@ -39,11 +39,13 @@ import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Map;
import java.util.NavigableMap;
import java.util.Random;
import java.util.TreeMap;
import java.util.concurrent.TimeUnit;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.function.UnaryOperator;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
@ -54,6 +56,9 @@ import java.util.stream.IntStream;
@Fork(3)
@State(Scope.Thread)
public class TreeMapUpdate {
@Param({"TreeMap", "descendingMap", "tailMap"})
public String mode;
@Param({"10", "1000", "100000"})
public int size;
@ -68,10 +73,25 @@ public class TreeMapUpdate {
private Supplier<TreeMap<Integer, Integer>> supplier;
private UnaryOperator<NavigableMap<Integer, Integer>> transformer;
private Integer[] keys;
@Setup
public void setUp() {
switch(mode) {
case "TreeMap":
transformer = map -> map;
break;
case "descendingMap":
transformer = map -> map.descendingMap();
break;
case "tailMap":
transformer = map -> map.tailMap(0, true);
break;
default:
throw new IllegalStateException(mode);
}
supplier = comparator ? () -> new TreeMap<>(Comparator.reverseOrder()) : TreeMap::new;
keys = IntStream.range(0, size).boxed().toArray(Integer[]::new);
Random rnd = seed == 0 ? new Random() : new Random(seed);
@ -86,12 +106,12 @@ public class TreeMapUpdate {
@Benchmark
public Map<Integer, Integer> baseline() {
// Just create map (empty or pre-filled)
return supplier.get();
return transformer.apply(supplier.get());
}
@Benchmark
public Map<Integer, Integer> put(Blackhole bh) {
Map<Integer, Integer> map = supplier.get();
Map<Integer, Integer> map = transformer.apply(supplier.get());
Integer[] keys = this.keys;
for (Integer key : keys) {
bh.consume(map.put(key, key));
@ -101,7 +121,7 @@ public class TreeMapUpdate {
@Benchmark
public Map<Integer, Integer> putIfAbsent(Blackhole bh) {
Map<Integer, Integer> map = supplier.get();
Map<Integer, Integer> map = transformer.apply(supplier.get());
Integer[] keys = this.keys;
for (Integer key : keys) {
bh.consume(map.putIfAbsent(key, key));
@ -111,7 +131,7 @@ public class TreeMapUpdate {
@Benchmark
public Map<Integer, Integer> computeIfAbsent(Blackhole bh) {
Map<Integer, Integer> map = supplier.get();
Map<Integer, Integer> map = transformer.apply(supplier.get());
Integer[] keys = this.keys;
for (Integer key : keys) {
bh.consume(map.computeIfAbsent(key, k -> k));
@ -121,7 +141,7 @@ public class TreeMapUpdate {
@Benchmark
public Map<Integer, Integer> compute(Blackhole bh) {
Map<Integer, Integer> map = supplier.get();
Map<Integer, Integer> map = transformer.apply(supplier.get());
Integer[] keys = this.keys;
for (Integer key : keys) {
bh.consume(map.compute(key, (k, old) -> k));
@ -131,7 +151,7 @@ public class TreeMapUpdate {
@Benchmark
public Map<Integer, Integer> computeIfPresent(Blackhole bh) {
Map<Integer, Integer> map = supplier.get();
Map<Integer, Integer> map = transformer.apply(supplier.get());
Integer[] keys = this.keys;
for (Integer key : keys) {
bh.consume(map.computeIfPresent(key, (k, old) -> k));
@ -141,7 +161,7 @@ public class TreeMapUpdate {
@Benchmark
public Map<Integer, Integer> merge(Blackhole bh) {
Map<Integer, Integer> map = supplier.get();
Map<Integer, Integer> map = transformer.apply(supplier.get());
Integer[] keys = this.keys;
for (Integer key : keys) {
bh.consume(map.merge(key, key, (k1, k2) -> k1));