build crash after extending oopDesc

[Krystal Mok]

On Sat, Jun 9, 2012 at 3:37 PM, John Rose <john.r.rose at oracle.com> wrote:

> Here's an old war-story:  When the original Hotspot team brought their
> prototype to Sun long ago, I was on the technical evaluation team.  One of
> my tests was to inject an extra field into class oopDesc.  (Specifically,
> the field held a string representation of the thread backtrace at the point
> of the object's allocation.  A crude allocation profiler!)  The system
> worked with a few edits and no further adjustment.  This demonstrated to me
> that the software architecture was robust and ready to evolve.
>

Always love to hear more about the history! Thanks for sharing ^_^


> (Things are different now.  The system is more than 10x larger.  It
> contains multiple platform ports, two good JITs, instrumentation, several
> GCs, and compressed pointers, none of which the prototype had.  I wish our
> system were still as malleable as it was when it was young, but it's a
> different engineering problem today.)
>
> Yes, I wish so, too.
(Reminds me of the work people are doing in the Labs, towards a more
modular VM [1]. It'd be really great if there's positive outcome from that
project. Although it's hard to tell whether or not HotSpot can benefit a
lot from these research, given its age, size and complexity today.)

- Kris

[1]: Christian Wimmer, Stefan Brunthaler, Per Larsen, Michael Franz,
"Fine-Grained Modularity and Reuse of Virtual Machine Components",
Modularity AOSD 2012


> — John
>
>
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