RFR: 8272783: Epsilon: Refactor tests to improve performance

[Aleksey Shipilev]

On Mon, 23 Aug 2021 12:53:18 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Epsilon tests run in tier1, and they take considerable time, especially on low-core machines. We can refactor and simplify some of the tests for better performance.
>> 
>> The improvements are:
>>   - Dropping test heap sizes to 64M..256M, which saves time zeroing/zapping the heap area;
>>   - Dropping some configurations, notably out-of-box `-Xbatch -Xcomp` (which makes little sense, as C1/C2 paths would be taken by other configs)
>> 
>> Additionally, run configurations were reformatted to avoid long lines.
>> 
>> 
>> $ make run-test TEST=gc/epsilon
>> 
>> # Before
>> real	1m28.297s
>> user	9m2.689s
>> sys	0m18.370s
>> 
>> # After
>> real	1m0.396s
>> user	6m27.221s
>> sys	0m13.499s
>
> Lgtm.

Thanks for review, @tschatzl!

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PR: https://git.openjdk.java.net/jdk/pull/5202