RFR: Prefer to take AOT method from the SC queue faster [v2]

[Aleksey Shipilev]

On Sat, 7 Sep 2024 06:59:33 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Probably WIP. Humor me for a second: why could not / should not we take the AOT task for "compilation" (installation, really) right away like this? I suspect when SC queues are overwhelmed with N elements, we keep walking the entire SC queue for no particular reason?
>> 
>> This improves javac benchmark considerably (look at both wall time and user time):
>> 
>> 
>> # BEFORE
>> Benchmark 1: build/linux-x86_64-server-release/images/jdk/bin/java -XX:CacheDataStore=app.cds -Xmx256m -Xms256m -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -cp JavacBenchApp.jar JavacBenchApp 50
>>   Time (mean ± σ):     348.3 ms ±   2.8 ms    [User: 949.0 ms, System: 101.4 ms]
>>   Range (min … max):   344.0 ms … 355.3 ms    100 runs
>> 
>> # AFTER
>> Benchmark 1: build/linux-x86_64-server-release/images/jdk/bin/java -XX:CacheDataStore=app.cds -Xmx256m -Xms256m -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -cp JavacBenchApp.jar JavacBenchApp 50
>>   Time (mean ± σ):     312.2 ms ±   2.6 ms    [User: 577.8 ms, System: 95.4 ms]
>>   Range (min … max):   307.1 ms … 318.5 ms    100 runs
>
> Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:
> 
>  - Drop SCC check from comparator
>  - Just return the SCC task right away
>  - Merge branch 'premain' into shortcut-aot-tasks
>  - Fix

Thanks!

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PR Comment: https://git.openjdk.org/leyden/pull/17#issuecomment-2336457593