RFR: [6904367]: (coll) IdentityHashMap is resized before exceeding the expected maximum size

[Peter Levart]

On 07/08/2014 11:30 PM, Martin Buchholz wrote:
> Benchmarks welcome.

I have run your latest webrev with the following benchamrk:

@State(Scope.Thread)
public class IHMBench {

     Map<Object, Object> map = new IdentityHashMap<Object, Object>();

     @Benchmark
     public void putNewObject(Blackhole bh) {
         Object o = new Object();
         bh.consume(map.put(o, o));
         if (map.size() > 100000) {
             map = new IdentityHashMap<Object, Object>();
         }
     }
}

Using:

java -Xmx4G -Xms4G -jar benchmarks.jar -f 0 -i 30 -wi 10 -t 1 -gc 1

...and results are:

Original:

Benchmark                     Mode   Samples        Score  Score 
error    Units
j.t.IHMBench.putNewObject    thrpt        30 13305370.384 80122.977    ops/s

Patched:

Benchmark                     Mode   Samples        Score  Score 
error    Units
j.t.IHMBench.putNewObject    thrpt        30 13364374.454 124491.206    
ops/s


Seems performance is the same.

Regards, Peter