JEP proposed to target JDK 13: 350: Dynamic CDS Archives

[Jiangli Zhou]

On Wed, May 1, 2019 at 8:25 AM Michael Bien <mbien42 at gmail.com> wrote:
>
> since each JVM process would create its own dynamic class data archive,
> on top of a static archive, i would assume that only the static archive
> would be shared between processes, while the dynamic archive would be
> mostly only beneficial for tuning startup time.
>
> Manually created static AppCDS archives on the other hand are fully
> shareable and can help with both, footprint and startup time.

With the traditional static archiving technology, memory sharing is
achieved when the same archived classes and shareable java objects are
loaded&used in different JVM processes. This is still the same for
dynamic archiving. The memory sharing benefit with
base_archive/dynamic_archive would be the same as a single static
archive when running the same Java application in different JVM
instances (on the same host).

Best,
Jiangli

>
> Would this be correct or is more sharing magic going on between those
> per-process archives?
>
> (i suppose you could just use the dynamic CDS feature once and use the
> dynamic archive just like it would be a second static & shareable archive)
>
> best regards,
> michael
>
> On 25.04.19 23:26, mark.reinhold at oracle.com wrote:
> > The following JEP is proposed to target JDK 13:
> >
> >    350: Dynamic CDS Archives
> >         https://openjdk.java.net/jeps/350
> >
> > Feedback on this proposal from JDK Project Committers and Reviewers [1]
> > is more than welcome, as are reasoned objections.  If no such objections
> > are raised by 23:00 UTC on Thursday, 2 May, or if they’re raised and
> > then satisfactorily answered, then per the JEP 2.0 process proposal [2]
> > I’ll target this JEP to JDK 13.
> >
> > - Mark
> >
> >
> > [1] https://openjdk.java.net/census#jdk
> > [2] https://cr.openjdk.java.net/~mr/jep/jep-2.0-02.html
>
>