[master] Integrated: 8264311: Heap object statistics

[Roman Kennke]

On Wed, 5 May 2021 14:17:34 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

> For Lilliput evaluation, it would be useful to be able to get some statistics about heap objects, e.g. how many objects there typically are, what is their (average) size, how big is the live data set, how many objecs have an identity hash code and how many objects are locked. Some of that information may be useful for general purpose too, e.g. the avg live data set and object size/count information might be quite useful to have.
> 
> Heap object statistics can be gathered and printed by invoking java with -XX:+UnlockDiagnosticVMOptions -XX:+HeapObjectStats -Xlog:heap+stats. It will impact performance of the workload. The sampling interval can be specificed by -XX:HeapObjectStatsSamplingInterval=X (in ms) and defaults to 500 (ms).
> 
> Testing:
>  - [x] Some manual tests, verifying the plausability of the output by hand
>  - [x] tier1
>  - [x] tier2

This pull request has now been integrated.

Changeset: dce94d8b
Author:    Roman Kennke <rkennke at openjdk.org>
URL:       https://git.openjdk.java.net/lilliput/commit/dce94d8bf8e6ba1b6b0a5d528ea3ba174ec80098
Stats:     253 lines in 6 files changed: 252 ins; 0 del; 1 mod

8264311: Heap object statistics

Reviewed-by: shade

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PR: https://git.openjdk.java.net/lilliput/pull/1