[aarch64-port-dev ] What next for aarch32

[Bob Vandette]

Ed,

Thanks for the great summary and your 30000ft view.  I agree with your
position and look forward to hearing the opinions of other aarch32 interested
parties.  I think there has to be much more discussion on exactly how the 64-bit
port consolidation occurs but we have plenty of time for that.

I’m willing to attend your fireside chat to listen to your members and answer any questions
you may have on our contribution.  Just send out the dial-in details if you’d like me to join.

Bob.

> On Oct 13, 2016, at 9:37 AM, Edward Nevill <edward.nevill at gmail.com> wrote:
> 
> [crossposted to aarch64 because of relevance there as well]
> 
> Hi,
> 
> So, having gone from a situation 18 months ago where the only port
> available in OpenJDK for aarch32 was the Zero port, we now find
> ourselves with an embarrassment of riches.
> 
> - The template interpreter port contributed by Linaro
> - The C1 port contributed by Azul
> - The C1/C2 port contributed by Oracle
> - We also have in the aarch32 port area, the Oracle C1/C2 port for
> aarch64 as it is integrally bound with the aarch32 port.
> 
> To this end I declare the aarch32 project a great success and would
> like to thank all those who have contributed to the project.
> 
> However, it does leave the question of what to do next.
> 
> My 30,000ft view is
> 
> - jdk8u aarch32
> 
> We should use the existing Azul port. I see no enthusiasim for
> backporting the Oracle C1/C2 port from jdk9 to jdk8u.
> 
> - jdk9 aarch32
> 
> We should use the Oracle port. Again I see no enthusiasm for forward
> porting the C1 port from jdk8u to jdk9 and even if it were forward
> ported it would still lack C2.
> 
> - jdk8u aarch64
> 
> Will continue to be supported as is by the aarch64 project
> 
> - jdk9 aarch64
> 
> We should use the existing port that has been developed as part of the
> OpenJDK process. It is the incumbant port and is used in
> Redhat/Ubuntu/Debian. It has been evaluated, tested and benchmarked by
> ARMs silicon partners and has also been evaluated by very large
> partners for use in large scale server applications. We cannot simply
> change the existing OpenJDK jdk9 aarch64 implementation without very
> good reason.
> 
> I am perfectly open to having the Oracle jdk9 port in the mainstream. I
> understand how it is integrally bound with the aarch32 port and it
> would be difficult and unnecessary to separate out the aarch32 port on
> its own for inclusion in jdk9. I think the --with-abi-
> profile=arm/aarch64 is acceptable even if it is not very pretty. I find
> the naming of the option "--with-abi-profile=xxx" fairly meanless and
> would prefer the more direct "--with-port=xxx".
> 
> Note that none of this is based on any technical merit of one port over
> another in terms of code quality, testing, benchmarking etc. It is
> simply preserving the status quo.
> 
> I think it will be difficult to get the aarch32 port into jdk9 because
> of the timescales. JDK 9 is now FC so no new features are accepted
> without an exception being raised. I am happy to try submitting a JEP
> to get it included, but I doubt it will be successful.
> 
> Our experience with the aarch64 port has taught us that it takes a lot
> longer than expected to merge a new port into the mainstream. I believe
> the process took about 6 months (Andew Haley may correct me on this).
> 
> Firstly we will need a sponsor within Oracle for the aarch32 port
> (Vladimer Koslov was the sponsor for the aarch32 port). Then the port
> will need to be merged to a 'staging' port so that it can be tested
> with Oracle's JPRT / Oracle's other internal tests. Finally it can be
> merged into the mainsteam.
> 
> This was the process followed for the aarch64 port. It may be possible
> to shorten some of this process as the code base is a well known
> quantity (at least within Oracle).
> 
> I think the best way forward with this is to have a discussion with the
> JDK 9 lead, Mark Reinhold, before firing off any JEPs etc.
> 
> We also need to have a discussion of interested parties within
> aarch32/aarch64 communities. I would prefer that as much of that
> discussion takes place in the open, either on the mailing list or in
> open conference calls although I appreciate there may be a need for
> private communications where commercial interests are involved.
> 
> I propose that we resurrect the 'fireside' chats which we had earlier
> in the year on the aarch64 project. These were held on every second
> Thursday at 15:00 UTC, so I would propose restarting these on Thurs
> 20th Oct.
> 
> Unfortunately, I do not have the facility to host these any longer.
> Stuart Monteith from Linaro was hosting these for a while. Stuart:
> Would you be able to host this. Alternatively, could someone else
> volunteer to host this?
> 
> All the best,
> Ed
>