[11u] RFC: Update Graal in OpenJDK 11 Updates?

[Gil Tene]

Sent from my iPad

> On Mar 13, 2020, at 1:04 AM, Langer, Christoph <christoph.langer at sap.com> wrote:
> 
> Hi Andrew, all,
> 
>> -----Original Message-----
>> From: Andrew Hughes <gnu.andrew at redhat.com>
>> Sent: Donnerstag, 12. März 2020 19:27
>> To: Langer, Christoph <christoph.langer at sap.com>; jdk-updates-
>> dev at openjdk.java.net; Andrew Dinn <adinn at redhat.com>; Severin
>> Gehwolf <sgehwolf at redhat.com>; Andrew Haley <aph at redhat.com>;
>> Thomas Wuerthinger <thomas.wuerthinger at oracle.com>; Doug Simon
>> <doug.simon at oracle.com>; Tom Rodriguez <tom.rodriguez at oracle.com>;
>> Volker Simonis <volker.simonis at gmail.com>
>> Subject: Re: [11u] RFC: Update Graal in OpenJDK 11 Updates?
>> 
>> 
>> 
>>> On 12/03/2020 12:03, Langer, Christoph wrote:
>>> Hi all,
>>> 
>>> as you may or may not know, the GraalVM Community Edition (CE)
>> supports OpenJDK 11 update releases. In order to do that, there exists a
>> clone of the OpenJDK repository in the GraalVM GitHub space [0]. This fork,
>> however, contains several additional patches, obviously mainly in the area of
>> JVMCI and the Graal compiler. There seems to be a certain interest of the
>> involved parties, that is, the GraalVM community, Oracle Labs and probably
>> also the OpenJDK community, to keep these repositories as close as possible.
>>> 
>>> One motivation could be to allow building of GraalVM native images from
>> OpenJDK distributions, such as mentioned in a GitHub issue raised against
>> the graal project [1].
>>> 
>>> Another motivation probably comes from the Graal community to reduce
>> the maintenance effort from merging the OpenJDK changes.
>>> 
>>> Furthermore, it has been policy in the OpenJDK 11 Updates project to try to
>> follow what Oracle is doing in their JDK 11 LTS update releases. Lately, there
>> obviously have been backports for JVMCI and Graal which completely don't
>> match with the current state of OpenJDK 11u. When researching this I
>> learned that the prerequisite of these kind of changes is a larger update of
>> JVMCI and Graal. The basis for this change could be a commit from the labs-
>> openjdk-11 Graal repository [2]. This would update JVMCI and Graal to the
>> state of OpenJDK 13. More details can be taken out of the conversation of
>> the GitHub issue [1].
>>> 
>>> I took this change, applied it to OpenJDK 11u-dev, resolved some conflicts
>> and made sure it builds on all platforms (that we support in the SAP team). A
>> prerequisite would also be a backport of JDK-8208686, at least the hotspot
>> part of it, as provided in [4]. The Graal/Java parts of JDK-8208686 are
>> contained in [3]. With this work applied, regression testing looks quite
>> promising. There are a few test failures in the NMT area, some crashes with
>> aot and a few minor Graal related test errors, but nothing that couldn't be
>> solved with too much of effort, I guess. But I can't make any judgement on
>> the state of the Graal compiler itself, since we don't have much test coverage
>> for that in our infrastructure.
>>> 
>>> However, the main point for me is to get a discussion started. First of all it is
>> about whether we want to have this kind of update at all in OpenJDK 11
>> Updates? If so, I'd need some help by people with expertise and test
>> infrastructure for the Graal related part. That's nothing we can cover in the
>> SAP team right now. If we decide against this update, we'll have give up our
>> policy about following the Oracle 11 Updates for JVMCI/Graal.
>>> 
>>> Looking forward to get input about this.
>>> 
>>> Thanks and best regards
>>> Christoph
>>> 
>>> [0] https://github.com/graalvm/labs-openjdk-11/
>>> [1] https://github.com/oracle/graal/issues/2196
>>> [2] https://github.com/graalvm/labs-openjdk-
>> 11/commit/fbbdf5f15300716110d2ac9b9bd7f70b03b35a7d
>>> [3] http://cr.openjdk.java.net/~clanger/webrevs/graal13.11u/
>>> [4] http://cr.openjdk.java.net/~clanger/webrevs/8208686.11u/
>>> 
>> 
>> I'm aware of these changes for Graal and have been working on getting
>> some of them into OpenJDK 11u.
>> 
>> I don't think we should just apply these monolithic commits, but instead
>> work out the relevant issues in OpenJDK 13 being backported and do it
>> correctly. We want 11u to be as maintainable as possible.
> 
> I've got some sympathy with that approach. We can certainly have a look to identify the single changes and try to apply them one by one... It'll probably also help to identify the sources of regressions when we run into some.
> 
> But, the general question that needs to be answered before is: Do we want this to happen at all? Any opinions/thoughts?

Can you elaborate on what we believe the Oracle 11u has done so far on this matter? 

> 
> Cheers
> Christoph