RFR: 8328278: Serial: Compute tenuring threshold before GC

[Albert Mingkun Yang]

On Fri, 15 Mar 2024 15:59:58 GMT, Guoxiong Li <gli at openjdk.org> wrote:

> Hi all,
> 
> This patch places the SerialGC code that computes tenuring threshold before per GC instead of after per GC, so that the method `AgeTable::print_on` prints the right tenuring threshold. Just like the current G1 implementation.
> 
> Thanks for taking the time to review.
> 
> Best Regards,
> -- Guoxiong

Thanks for the explanation.

> Print the threshold and the age table.

I think there are two possible interpretations re the printed value here:

1. the printed threshold and age-table are directly related -- the threshold is calculated from the age-table.

2. the printed threshold and age-table are corresponding to the just finished gc-pause (since printing is at the end of gc-pause). IOW, threshold is used during scavenging and age-table is populated during scavenging.

I think what you have in mind is 2 (right?), and that is what G1 does.

It's not obvious that one is more "correct" than the other. (My first impression is 1, since `AgeTable` has a method to calculate the threshold.)

-------------

PR Comment: https://git.openjdk.org/jdk/pull/18329#issuecomment-2004408424