RFR: 8269823: JFR: Eliminate 'is_large' check for native JFR event if the size range is certain [v5]

[Denghui Dong]

On Thu, 8 Jul 2021 04:46:18 GMT, Denghui Dong <ddong at openjdk.org> wrote:

>> Hi,
>> 
>> Could I have a review of this improvement that eliminates 'is_large' check if the event size range is certain?
>> 
>> JDK-8246260 introduced event large checks to reduce the recording size.
>> This check could be eliminated at compile/build time when one of the following conditions is satisfied:
>> 1. if the max size is < 128
>> 2. if the min size is >= 128
>> 
>> The max size and the min size could be computed for the most native events at the generation phase.
>> 
>> And I think this improvement may also be done for JDK events.
>
> Denghui Dong has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix

hmm, sorry, my previous benchmark result is tested without enabling the event.

The following are the latest test results on Linux x86_64:

with the patch:

Benchmark                    Mode  Samples       Score  Score error  Units
o.s.MyBenchmark.testEmit    thrpt       20  250838.078     1850.396  ops/s


without the patch:

Benchmark                    Mode  Samples       Score  Score error  Units
o.s.MyBenchmark.testEmit    thrpt       20  239574.823     1242.553  ops/s

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PR: https://git.openjdk.java.net/jdk/pull/4670