RFR: 8356000: C1/C2-only modes use 2 compiler threads on low CPU count machines [v2]

[Aleksey Shipilev]

On Mon, 5 May 2025 07:18:23 GMT, Damon Fenacci <dfenacci at openjdk.org> wrote:

>> 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 seven additional commits since the last revision:
>> 
>>  - Better test, patch amendments
>>  - Merge branch 'master' into JDK-8356000-c1-c2-compiler-count
>>  - Merge branch 'master' into JDK-8356000-c1-c2-compiler-count
>>  - Unnecessary arch limitation
>>  - Simplify test
>>  - Adjust test bound
>>  - Fix
>
> test/hotspot/jtreg/compiler/arguments/TestCompilerCounts.java line 64:
> 
>> 62:             ProcessBuilder pb = ProcessTools.createLimitedTestJavaProcessBuilder(args);
>> 63:             OutputAnalyzer output = new OutputAnalyzer(pb.start());
>> 64:             output.shouldHaveExitValue(0);
> 
> I was wondering if we should check the output as well, e.g. with a test that prints the actual number of compiler threads (like the one in the description, to make it a bit more like a regression test).

Added the test now! Took a while to figure out how to do it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24972#discussion_r2112239915