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MINOR: Fix needless GC + Result time unit in JMH 

Fixes two issues with the JMH benchmark example:
* Trivial: The output should be in `ops/ms` for readability
reasons (it's in the millions of operations per second)
* Important: The benchmark is not actually measuring the
LRU Cache performance as most of the time in each run is
wasted on concatenating `key + counter` as well as
`value + counter`. Fixed by pre-generating 10k K-V pairs
(100x the cache capacity) and iterating over them. This
brings the performance up by a factor of more than 5 on
a standard 4 core i7 (`~6k/ms` before goes to `~35k/ms`).

Author: Armin Braun <me@obrown.io>

Reviewers: Bill Bejeck <bbejeck@gmail.com>, Guozhang Wang <wangguoz@gmail.com>, Ismael Juma <ismael@juma.me.uk>

Closes #2903 from original-brownbear/fix-jmh-example
This commit is contained in:
Armin Braun 2017-09-18 10:38:26 +01:00 committed by Ismael Juma
parent a3f068e22d
commit 346d0ca538
1 changed files with 22 additions and 6 deletions
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28
jmh-benchmarks/src/main/java/org/apache/kafka/jmh/cache/LRUCacheBenchmark.java vendored
View File

@ -17,9 +17,11 @@
package org.apache.kafka.jmh.cache;
import java.util.concurrent.TimeUnit;
import org.apache.kafka.common.cache.LRUCache;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.Level;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
@ -35,25 +37,39 @@ import org.openjdk.jmh.runner.options.OptionsBuilder;
* http://hg.openjdk.java.net/code-tools/jmh/file/tip/jmh-samples/src/main/java/org/openjdk/jmh/samples/
*/
@State(Scope.Thread)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
public class LRUCacheBenchmark {
private static final int DISTINCT_KEYS = 10_000;
private static final String KEY = "the_key_to_use";
private static final String VALUE = "the quick brown fox jumped over the lazy dog the olympics are about to start";
private final String[] keys = new String[DISTINCT_KEYS];
private final String[] values = new String[DISTINCT_KEYS];
private LRUCache<String, String> lruCache;
private final String key = "the_key_to_use";
private final String value = "the quick brown fox jumped over the lazy dog the olympics are about to start";
int counter;
@Setup(Level.Trial)
public void setUpCaches() {
public void setUp() {
for (int i = 0; i < DISTINCT_KEYS; ++i) {
keys[i] = KEY + i;
values[i] = VALUE + i;
}
lruCache = new LRUCache<>(100);
}
@Benchmark
public String testCachePerformance() {
counter++;
lruCache.put(key + counter, value + counter);
return lruCache.get(key + counter);
int index = counter % DISTINCT_KEYS;
String hashkey = keys[index];
lruCache.put(hashkey, values[index]);
return lruCache.get(hashkey);
}
public static void main(String[] args) throws RunnerException {