RFR: 8276764: Enable deterministic file content ordering for Jar and Jmod

[Andrew Leonard]

On Thu, 18 Nov 2021 11:42:48 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>>> Just to verify, this test jar had 16000 files in a single directory? Since having 100 files in 160 directories would not have the same impact, right?
>> 
>> @magicus so the first test I did was 16,000 files in multiple directories, as I thought that was more representative, and would involve multiple small sorts vs one large sort.
>> I have just re-run the tests again, for both 16000 multi-dir and 16000 single dir, and the results are similar:
>> 16000 multi-dir x50:
>> Existing code: 291 seconds (variance: +/- 3 seconds)
>> New patch:  293 seconds (variance: +/- 3 seconds)
>> 16000 single-dir x50:
>> Existing code: 235 seconds (variance: +/- 3 seconds)
>> New patch: 237 seconds (variance: +/- 3 seconds)
>
> @andrew-m-leonard Thanks. I think that alleviates any fear of performance regression. Sounds like you are well within the span of normal variation.

@magicus I've added updates to the jar and jmod man pages, as "Notes" about ordering, does that sound reasonable?

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PR: https://git.openjdk.java.net/jdk/pull/6395