Integrated: 8330969: scalability issue with loaded JVMTI agent

[Serguei Spitsyn]

On Wed, 24 Apr 2024 16:04:30 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

> This is a fix of the following JVMTI scalability issue. A closed benchmark with millions of virtual threads shows 3X-4X overhead when a JVMTI agent has been loaded. For instance, this is observable when an app is executed under control of the Oracle Studio `collect` utility.
> For performance analysis, experiments and numbers, please, see the comment below this description.
> 
> The fix is to replace the global counter `_VTMS_transition_count` with the mark bit `_VTMS_transition_mark` in each `JavaThread`'.
> 
> Testing:
>  - Tested with mach5 tiers 1-6

This pull request has now been integrated.

Changeset: 663acd2e
Author:    Serguei Spitsyn <sspitsyn at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/663acd2e173114fec7c2f50084af9ec56150d394
Stats:     42 lines in 5 files changed: 14 ins; 11 del; 17 mod

8330969: scalability issue with loaded JVMTI agent

Reviewed-by: amenkov, cjplummer

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PR: https://git.openjdk.org/jdk/pull/18937