RFR: 8377797: Remove SA support for MethodData and the printmdo command [v3]

[Coleen Phillimore]

On Sat, 14 Feb 2026 05:02:32 GMT, Yasumasa Suenaga <ysuenaga at openjdk.org> wrote:

>> Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove the doc.
>
> Actually `printmdo` is not so needed for troubleshooting POV, but it is useful for learning HotSpot and JIT compiler behavior IMHO (I gave a talk about MDO in relation to JVMCI in past ( @ Java Day Tokyo 2017)). Replay data might be much better as you wrote in CSR, but it is difficult to extract MDO from that, and also it is difficult to check realtime data (e.g. num of branches).
> 
> I do not have big objections for removing `printmdo`, but I think it is better if we can keep it for learning HotSpot if possible. I'm not familiar with Valhalla, but I want to know whether it needs big changes to support `printmdo`.

@YaSuenag for your usage, I think a jcmd would be a better place to support this, rather than a Java copy of this code that can and will become out of date.  I'll file an RFE for that, and could you elaborate in that RFE?

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PR Comment: https://git.openjdk.org/jdk/pull/29693#issuecomment-3914758515