Hotspot Express (HSX)

[Ioi Lam]

On 2/28/20 10:03 AM, Volker Simonis wrote:
> On Fri, Feb 28, 2020 at 5:45 PM Dalibor Topic <dalibor.topic at oracle.com> wrote:
>>
>>
>> On 28.02.2020 12:29, Volker Simonis wrote:
>>
>>> I just want to re-iterate one more time:
>>>    - this proposal is not about changing jdk tip or jdk tip development
>>>    - it's also not about changing how the updates project is run
>>>
>>> The proposal is about evaluating the advantages and drawbacks of HSX
>>> in a new  project. It would be nice to have such a project under the
>>> OpenJDK umbrella, but if nobody is interested at all, it can just as
>>> well be developed independently.
>> Hi Volker,
>>
>> I have to admit that I'm still a bit confused about the scope of the
>> proposal, as it sounded to me a few days ago as if this was a proposal
>> to modify the jdk11u/jdk11u repository in some way or another, or maybe
>> even to establish another jdk11u/jdk11u-hsx (?) repository within the
>> JDK Updates Project.
>>
>> Now it sounds like you're thinking about creating a new OpenJDK Project
>> instead.
>>
>> So maybe it would be helpful to start a new thread which more plainly
>> states what the suggested scope is instead of continuing to get deeper
>> into the back and forth of this thread, as I suspect the number of
>> people who can follow all this and still understand it is getting
>> smaller with each further e-mail. ;)
>>
> Hi Dalibor,
>
> this thread is the discussion about a concept. The concept is called
> HotSpot Express (HSX). More senior colleagues will remember it from
> the old jdk 6,7,8 days. I think Paul described it pretty well in his
> initial mail, but in short, "in the HotSpot Express release model, new
> versions of HotSpot are drawn from its leading development line ...
> and prepared for delivery as product-quality JVMs" in older JDK
> releases. This is by the way cited directly from Erik Trimble's
> Project proposal from 2009 [1]. For those of you who like software
> archeology, I strongly recommend another of Erik's mails [2] where he
> describes in great detail how this process worked for jdk 7 and 8. And
> by the way, everybody who ever used Oracle JDK 6 & 7 has already used
> HSX.
>
> What you are asking now, is how this concept can be implemented? Of
> course there are plenty of possibilities for doing that and the
> details are obviously not decided yet. That's what this thread has
> been created for in the first place.
>
> HSX can be a sub-project of the Updates project in which case it would
> get its own repository as you suggested (maybe jdk11u/jdk11u-hsx ?).
> If it is successful and the jdk11u maintainers like it, it may even be
> merged into jdk1u/jdk11u eventually. On the other hand, if there's
> absolutely no interest in the HSX project from the people involved in
> the Updates Project, HSX might be developed in its own OpenJDK
> Project, which still would have to be proposed and created. As a last
> resort, if nobody in the OpenJDK community at all is interested in
> HSX, there's still the possibility to develop it in a downstream
> project.

Without expressing my opinion whether HSX is a good idea (I do have an 
opinion :-), I would encourage the HSX proponents to consider what the 
implementation would look like.

The old implementation of HSX just drops in a new HotSpot VM (libjvm.so) 
into an older JDK, and that puts a lot of burden on HotSpot development. 
It was also done in an era where the "JDK" was just the library and 
"HotSpot" was the language execution engine. However, today large parts 
of the execution engine (e.g., Lambda) is implemented inside JDK core 
libs and are inseparable from the corresponding version of libjvm.so.

So if the proposal is "let's go back to the old way", that's simply 
impossible.

I think for the HSX idea to get traction, we need a more concrete 
proposal of

- what part of a new JDK release will be extracted and installed into an 
older release
- what's the extraction/installation model?
   - Just copy binary files?
   - Manipulation of binary files by tools (jlink??)
   - source level rebuild?

If we just keep arguing on the merits of the "idea", it will probably 
not go anywhere.

Thanks
- Ioi



> You see, all pretty simple. No need to worry :)
> We got exactly what we wanted - a discussion about HotSpot Exress in a
> thread called "Hotspot Express (HSX)".
>
> Regards,
> Volker
>
> PS: Ceci n'est pas HotSpot Exress [3] :)
>
> [1] http://mail.openjdk.java.net/pipermail/jdk7u-dev/2011-August/000160.html
> [2] http://mail.openjdk.java.net/pipermail/jdk7u-dev/2011-August/000160.html
> [3] https://en.wikipedia.org/wiki/The_Treachery_of_Images
>
>> cheers,
>> dalibor topic
>>
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