Greetings again,

A more straightforward implementation has been pushed for JEP Cooperative JFR 
Sampling [1].

The ambition and the hopes are that the porting work involved will be much more 
straightforward.

In summary, the original design, premised on a preemptive move of the FP 
register in the interpreter, has been abandoned due to the complexities 
involved in its implementation for all platforms.

A more straightforward solution, which should involve significantly less 
porting work, has therefore been pushed to the PR [2].

Please take a look.

Thanks
Markus

[1] https://openjdk.org/jeps/8350338
[2] https://github.com/openjdk/jdk/pull/24296


-----Original Message-----
From: Markus Gronlund 
Sent: Monday, 12 May 2025 18:21
To: porters-dev <porters-dev@openjdk.org>
Cc: Markus Gronlund <markus.gronl...@oracle.com>
Subject: RE: JEP : Cooperative JFR Sampling (porting work)

Friendly reminder since the JEP has moved to Candidate.

Thanks
Markus

-----Original Message-----
From: porters-dev <porters-dev-r...@openjdk.org> On Behalf Of Markus Gronlund
Sent: Thursday, 24 April 2025 00:53
To: porters-dev <porters-dev@openjdk.org>
Subject: JEP : Cooperative JFR Sampling (porting work)

Greetings,

I am sending this to the porters-dev list as a heads-up for changes involved in 
JEP Cooperative JFR Sampling [1], which will affect ports if you support the 
JDK Flight Recorder (JFR) system.

The TemplateInterpreter will need a few changes; please see the files listed in 
the PR [2].

Technically, the InterpreterMacroAssembler::remove_activation() function will 
change to pre-emptively move the frame pointer (fp) to the sender frame before 
issuing a safepoint poll.

No stubs will be provided because the overall changes are extensive and 
completely change how the JFR system works regarding sampling.

Please feel free to send me patches, and I will incorporate them into the 
overall PR, or you can wait for a potential integration.

I appreciate your cooperation.
Markus

[1] https://openjdk.org/jeps/8350338
[2] https://github.com/openjdk/jdk/pull/24296

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