Integrated: 8334513: New test gc/TestAlwaysPreTouchBehavior.java is failing on MacOS aarch64

Thomas Stuefe stuefe at openjdk.org
Sat May 24 09:54:55 UTC 2025


On Thu, 22 May 2025 07:41:28 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> I exhumed this old issue that fell through the cracks.
> 
> The test wants to make sure AlwaysPreTouch works by pretouching the java heap and comparing RSS with heap size. 
> 
> This technique is shaky: if the host machine experiences memory pressure, part of the pretouched memory will be swapped out before we measure RSS.
> 
> There is no way to make this bulletproof; still, this test is too useful to abandon it. Therefore I modified this test to make false positives (hopefully) very unlikely. See comment in test for details.
> 
> See old PR: https://github.com/openjdk/jdk/pull/19803

This pull request has now been integrated.

Changeset: e8933057
Author:    Thomas Stuefe <stuefe at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/e89330579d5f38e282512211711fffeeea3e899e
Stats:     90 lines in 5 files changed: 58 ins; 12 del; 20 mod

8334513: New test gc/TestAlwaysPreTouchBehavior.java is failing on MacOS aarch64

Reviewed-by: mbaesken, aph

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PR: https://git.openjdk.org/jdk/pull/25384


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