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

[Peter Levart]

On 07/13/2014 01:24 PM, Jeff Hain wrote:
> On 07/08/2014 10:07 PM, Martin Buchholz wrote:
>> I updated my webrev and it is again "feature-complete".
>> http://cr.openjdk.java.net/~martin/webrevs/openjdk9/IdentityHashMap-capacity/
>> <http://cr.openjdk.java.net/%7Emartin/webrevs/openjdk9/IdentityHashMap-capacity/>
>> (old webrev at
>> http://cr.openjdk.java.net/~martin/webrevs/openjdk9/IdentityHashMap-capacity.0/
>> <http://cr.openjdk.java.net/%7Emartin/webrevs/openjdk9/IdentityHashMap-capacity.0/>
>> )
> The additional loop hurts in my benchmarks (10-15 percents slower).
> If removing it and adding a specific putAfterResize() method (without the
> "item == k" test), replacing "continue" with "return putAfterResize(k, value)",
> it's much better.
>
> NB: In one bench I clear the map each time it hits 1000 mappings,
> so that it always fit in some cache, which is about 4 times faster
> than going up to 1000*1000 mappings (clear() cost included), and
> make put internals costs variations more obvious (hopefully).
>
> -Jeff

Can you post the benchmark source?

Thanks, Peter