[jdk16] RFR: 8258985: Parallel WeakProcessor may use too few threads [v2]

[Stefan Johansson]

On Fri, 8 Jan 2021 12:48:14 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

>> Please review this fix to the parallel WeakProcessor's computation of the
>> number of worker threads to use.  It was previously limited by the current
>> value of active_workers(), whatever that happens to be.  It should be
>> limited by total_workers(), just as with the parallel ReferenceProcessor.
>> (Both are subject to ReferencesPerThread.)
>> 
>> Testing
>> mach5 tier1
>> Some hand testing (Linux-x64) to verify the expected number of threads are
>> being used.
>> 
>> Note: That hand testing suggests some further tuning of ReferencesPerThread
>> might be in order. With the current default of 1000, I often saw in testing
>> that some threads were started late enough that no work was left for them.
>> I'll file a separate RFE for that.
>
> Kim Barrett has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix doc comments about number of threads used

Marked as reviewed by sjohanss (Reviewer).

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PR: https://git.openjdk.java.net/jdk16/pull/75