RFR: JDK-8283674: Pad ObjectMonitor allocation size to cache line size

[David Holmes]

On Mon, 28 Mar 2022 05:35:27 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> If padding was necessary before, would it not be necessary now too?

We don't know that it was _necessary_ before, only that it was present - the alignment aspect may have been more important than actual cache-line padding. If someone wanted to add padding anywhere today we would want performance numbers to show it is needed. So adding back padding that we have removed, and with which no performance regression has been attributed, should be held to the same standard IMO.

Cheers,
David

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PR: https://git.openjdk.java.net/jdk/pull/7955