RFR: 8305753: Allow JIT compilation for -Xshare:dump [v2]

[David Holmes]

On Wed, 18 Oct 2023 22:47:57 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> This RFE makes it possible for the user to enable the JIT compiler during the CDS dump by specifying `-Xshare:dump -Xmixed`
>> 
>> By default, `-Xshare:dump` runs with `-Xint`. This maintains the previous behavior.
>> 
>> Which mode to use?
>> 
>> - Dumping in `-Xint` mode is faster when the classlist is small. `-Xint` is also required for deterministic dumping (compiler threads can change the order of the archived object).
>> 
>> - However, dumping in `-Xmixed` mode is faster when the class list is larger. We also need to run the compiler in Leyden so that we can generate the CDS archive and AOT code at the same time.
>> 
>> 
>> Tested with tiers 1-4 and builds-tier5.
>
> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
> 
>   @calvinccheung review comments

For this to be useful in mainline, per the example given, then users have to be very aware of its existence. A Release Note is not sufficient, this needs to be documented in the Java command reference (manpage) as well. Thanks.

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PR Comment: https://git.openjdk.org/jdk/pull/16233#issuecomment-1769761709