RFR: 8279508: Auto-vectorize Math.round API [v9]

[Jatin Bhateja]

On Thu, 10 Mar 2022 14:29:36 GMT, Joe Darcy <darcy at openjdk.org> wrote:

>> Hi @jddarcy , 
>> 
>> Test has been modified on the same lines using generic options which manipulate compilation thresholds and agnostic to target platforms.
>> 
>>  * @run main/othervm -XX:Tier3CompileThreshold=100 -XX:CompileThresholdScaling=0.01 -XX:+TieredCompilation RoundTests
>> 
>> Verified that  RoundTests::test* methods gets compiled by c2.
>> Test execution time with and without change is almost same ~7.80sec over Skylake-server.
>> 
>> Regards
>
> To be more explicit, the existing RoundTests.java test runs in a fraction of a second.  The updated test runs many times slower, even if now under 10 second, at least on some platforms.
> 
> Can something closer to the original performance be restored?
> 
> As a tier 1 library test, these tests are run quite frequently.

Hi @jddarcy , 
Earlier none of the test methods in  RoundTests.java were compiled on account of low invocation count,  a loop with 2000 iterations under the influence controlled compilation threshold now triggers tier4 compilation of test points. I did several runs in Skylake machine with patch and without patch and could see no perceptible difference in runtime due to modification.

I have further reduced the invocation count and compile threshold.

Thanks

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PR: https://git.openjdk.java.net/jdk/pull/7094