Integrated: 8295267: Improve G1 scan to merge ratio calculation

[Thomas Schatzl]

On Thu, 13 Oct 2022 11:57:21 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

> Hi all,
> 
>   can I have reviews for this change that fixes the merge-to-scan ratio calculation ("which fraction of the remembered sets creates unique cards") for predictions to make it more accurate and understandable?
> 
> Previously the denominator has been the total number of scanned cards; this seems to be a good approximation (trying to make a case for it, it's wrong) if the number of log buffers is low at GC start, but tends to get broken otherwise (i.e. with [JDK-8137022](https://bugs.openjdk.org/browse/JDK-8137022)).
> 
> This change fixes this to use the number of cards that were merged in.
> 
> This change depends on PR#10656. Please review that one first if not done otherwise.
> 
> Testing: tier1, checking that no tests use the "Dirty Cards" string now changed.
> 
> Thanks,
>   Thomas

This pull request has now been integrated.

Changeset: 2e2a51ee
Author:    Thomas Schatzl <tschatzl at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/2e2a51ee22068e847b36f9a5f20bd37050eaabf8
Stats:     50 lines in 8 files changed: 4 ins; 11 del; 35 mod

8295267: Improve G1 scan to merge ratio calculation

Reviewed-by: ayang, iwalulya

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PR: https://git.openjdk.org/jdk/pull/10694