Integrated: 8281318: Improve jfr/event/allocation tests reliability

[Aleksey Shipilev]

On Mon, 7 Feb 2022 09:34:15 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> This fixes the failure on x86_32 by resolving an object/TLAB "sizing" problem. On x86_32, the 100K object gets 200K TLAB, which allocates the next object exactly in the same TLAB. Bumping the object size to 128K resolves this.
> 
> Additionally, rewired the tests to match object sizes exactly. In modern JDK, the header size depends on `UseCompressedClassPointers`, not on `UseCompressedOops`. Using `Whitebox`, we can poll the VM configuration exactly.
> 
> Additional testing: 
>  - [x] Linux x86_32 fastdebug, `jfr/event/allocation/`
>  - [x] Linux x86_64 fastdebug, `jfr/event/allocation/`, out of the box
>  - [x] Linux x86_64 fastdebug, `jfr/event/allocation/`, with `-XX:-UseCompressedClassPointers`

This pull request has now been integrated.

Changeset: 65831eb2
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/65831eb294b6f1f5f99988836c00005d41c27fd3
Stats:     54 lines in 3 files changed: 33 ins; 0 del; 21 mod

8281318: Improve jfr/event/allocation tests reliability

Reviewed-by: mgronlun

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PR: https://git.openjdk.java.net/jdk/pull/7365