RFR: 8278282: G1: Log basic statistics of evacuation failure

[Thomas Schatzl]

On Thu, 16 Dec 2021 09:29:09 GMT, Hamlin Li <mli at openjdk.org> wrote:

> The original pr is at #6763 , which should be retired as we have decided to adjust part of optimization solution for evacuation failure (see #6627 for details), so the log will be adjusted accordiingly.
> The basic log related to evacuation failed will looks like below based on this patch.
> 
> 
> [13.126s][debug][gc,phases] GC(0)       Restore Retained Regions (ms): Min:  0.0, Avg: 197.4, Max: 1579.1, Diff: 1579.1, Sum: 1579.1, Workers: 8
> [13.126s][debug][gc,phases] GC(0)         Evacuation Failure Regions:    Min: 1, Avg:  1.0, Max: 1, Diff: 0, Sum: 1, Workers: 1

Lgtm apart from the omission of that log message check.

I assume that it's just not worth adding log messages for the sub phases (sorting, ...) of the evacuation failure handling since we decided on the other option using the prev bitmap already. That's fine.
In any case we can always improve these messages.

test/hotspot/jtreg/gc/g1/TestGCLogMessages.java line 268:

> 266:         new LogMessageWithLevel("Recalculate Used Memory", Level.DEBUG),
> 267:         new LogMessageWithLevel("Restore Preserved Marks", Level.DEBUG),
> 268:         new LogMessageWithLevel("Restore Retained Regions", Level.DEBUG),

Please also check the work item in this test. Needs to be added just here.

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

Marked as reviewed by tschatzl (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6860