Struct/value types + stack allocations

Vitaly Davidovich vitalyd at
Wed Jan 18 20:41:43 PST 2012

Hi John,

Sorry, let me clarify - I'm not saying that this is a priority for me in
the sense that it's preventing me from accomplishing something concrete.
Rather, it's something that I (and I think a substantial populace of other
java developers) would really like to see in java and the VM.  I'm not sure
how projects are selected for implementation by Oracle (e.g. how did
invokedynamic, which is mostly useful for dynamic languages and not java,
get Oracle engineers allocated to it? Did someone external contribute a
preliminary prototype first?) but I was hoping that I could make a decent
case for why something like this would be very welcomed by the java
community and why I think it should get *relative* priority to other
projects under consideration.

Feel free to move this conversation to mlvm (or something else) as it's
getting a bit exploratory.


Sent from my phone
On Jan 18, 2012 8:59 PM, "John Pampuch" <john.pampuch at> wrote:

> **
> Vitaly-
> I think contributing to OpenJDK is the best way to express your priorities
> :)
> The Java language probably wouldn't have constructs in it that could
> leverage a mechanism like this for a long time (if ever).  Would you mind
> sharing why this is a priority for you?
> -John
> On 1/18/12 4:39 PM, Vitaly Davidovich wrote:
> I also see my phone auto-corrected as heal instead of heel ... :)
> To John, albeit selfishly :), I'd love to see structs prioritized over
> fixnums and maybe some of the other things (reification would be great too
> and would go a long way in reducing bloat due to boxed numerics).  Is there
> something akin to public voting on prioritization of features that Oracle
> agrees to dedicate resources to? Maybe I'm overestimating demand, but I
> think structs would get a lot of backing.
> Thanks
> Sent from my phone
> On Jan 18, 2012 5:01 PM, "Ismael Juma" <mlists at> wrote:
>> Hi all,
>> Vitaly Davidovich <vitalyd at ...> <vitalyd at ...> writes:
>> > The reason I ask is because I think the achilles heal of java
>> performance
>> > is the memory consumption (this is something you often hear in
>> discussions
>> > about java performance).
>> Agreed. I've seen and written tons of code to workaround the fact that
>> there are
>> no structs in the language. Examples of popular open-source projects that
>> use
>> parallel arrays (with much worse cache locality) to avoid objects and
>> their
>> memory overhead are many (Lucene, Mahout, fastutil, Trove, JGit, etc.).
>> Best,
>> Ismael
-------------- next part --------------
An HTML attachment was scrubbed...

More information about the hotspot-runtime-dev mailing list