[intrinsics] performance improvements for the intrinsified version of Objects::hash

[Vicente Romero]

Hi all,

I have produced a new iteration of performance results with a 
reorganization of the data proposed by Alex, see [1], I added a link to 
the benchmark source

Thanks
Vicente

[1] 
http://cr.openjdk.java.net/~vromero/intrinsics_benchmark_results/v5/benchmarkResults_intrinsics_all_data_v5.html

On 3/4/19 9:52 PM, Vicente Romero wrote:
>
>
> On 3/4/19 8:11 PM, Alex Buckley wrote:
>> // Adopting a zero-decimal-places policy because precision to 
>> multiple decimal places is less important than accuracy and 
>> repeatability.
>>
>> On 3/4/2019 4:28 PM, Vicente Romero wrote:
>>> I have uploaded another round of experiments for Objects::hash, see 
>>> [1].
>>> The main variation I have included a variant of most of the tests in
>>> which instead of invoking Objects::hash 10 times sequentially, the same
>>> invocation occurs inside a loop which is executed 10 times. This shows
>>> that when the call site is reused, the execution time trumps vanilla
>>> JDK13 most of the time.
>>
>> That's not really the story though :-) Yes, the *Int*StringsLoop10 
>> tests run faster with intrinsified invocation than with vanilla 
>> invocation, but generally, the *Int*StringsLoop10 tests enjoy less 
>> impressive speedups than the *Int*Strings tests. (Example: 
>> 25Int25Strings gets a 21x speedup, but 25Int25StringsLoop10 only gets 
>> a 2x speedup.)
>>
>> This is because the *Int*StringsLoop10 tests already run faster on 
>> vanilla JDK 13 than the *Int*Strings tests, presumably thanks to 
>> inlining ("the call site is reused").
>>
>> I guess that 1IntLoop10, 2IntsLoop10, and 2Ints2StringsLoop10 would 
>> have such high throughput on vanilla JDK 13 that their speedups with 
>> intrinsification might be significantly <1.
>
> not in all cases, see [1] the new information is highlighted in yellow
>>
>> Alex
>
> Vicente
>
> [1] 
> http://cr.openjdk.java.net/~vromero/intrinsics_benchmark_results/benchmarkResults_intrinsics_all_data_v4.html