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

[Kim Barrett]

On Fri, 1 Jan 2021 10:02:10 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.

This pull request has now been integrated.

Changeset: efc36be5
Author:    Kim Barrett <kbarrett at openjdk.org>
URL:       https://git.openjdk.java.net/jdk16/commit/efc36be5
Stats:     11 lines in 2 files changed: 5 ins; 0 del; 6 mod

8258985: Parallel WeakProcessor may use too few threads

Use total workers rather than active.

Reviewed-by: tschatzl, ayang, sjohanss

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