Merging jdk9/hs-rt with jdk9/hs

[Mikael Vidstedt]

Alejandro,

As we discussed offline let's try to keep most of this the same way 
we're doing it today. You'll keep doing the jdk9/dev <-> jdk9/hs 
integrations, PIT submissions, etc. As you point out, instead of using 
latest/greatest in jdk9/hs the gatekeeper will have to provide you with 
a set of tips for you to use, but apart from that there should hopefully 
be very few actual changes to the process.

Cheers,
Mikael

On 4/7/2016 12:32 PM, Alejandro Murillo wrote:
>
> Hi Mikael,
> I apologize I missed your original email. Just seeing this now.
>
> You don't mention the plans about gate-keeping,
> will the hs-rt gatekeeper will also also assume the
> synching with dev,  and therefore the submission of PIT,  etc?
>
> If not, since main will be constantly changing, I will need
> to be provided with the tips of a stable snapshot to merge with dev to 
> run pit.
> And then a hint of when to push the merge back to main.
> Since we have to push with JPRT,  there are some situations for 
> potential problems here.
>
> Of course, that's not different to what is currently done to merge 
> jdk9/dev to master,
> except that we now have mach5 to pin point stable jdk9/dev snapshots,
> and also,  there's nothing coming back from master to dev weekly
> (except tags) and once in a while special integrations.
> And as mentioned above, with hs repos, we use JPRT to push
>
> Thanks
> Alejandro
>
>
> On 4/6/2016 4:19 PM, Mikael Vidstedt wrote:
>>
>> Having heard no feedback[1], we're going to go ahead with this 
>> experiment and the plan is to do the switch next week, *Friday April 
>> 15th*. Again, please note that any outstanding work based on 
>> jdk9/hs-rt will have to be rebased on jdk9/hs once the switch is 
>> made. More information as we get closer to the actual switchover.
>>
>> Let us know if you have any concerns with the date, and/or any 
>> feedback on how it's working out.
>>
>> Cheers,
>> Mikael
>>
>> [1] Not even from Volker *hint* ;)
>>
>> On 3/21/2016 4:59 PM, Mikael Vidstedt wrote:
>>>
>>> All,
>>>
>>> The JDK 9 development of Hotspot is primarily done in two different 
>>> mercurial forests: jdk9/hs-rt[1], and jdk9/hs-comp[2]. In June of 
>>> last year we moved[3] all the GC development from jdk9/hs-gc[4] to 
>>> jdk9/hs-rt, and the experience so far has been a good one. Change 
>>> propagation (from jdk9/hs-rt to jdk9/hs-gc and vice verse) is now a 
>>> non-issue, we get testing faster on the union of the changes where 
>>> previously it could take weeks to catch a GC related bug in RT 
>>> testing, etc.
>>>
>>> However, both jdk9/hs-rt and jdk9/hs-comp still integrate through a 
>>> third forest - jdk9/hs[5], aka. hs "main" - before the changes are 
>>> integrated to jdk9/dev[6]. In line with the previous simplification, 
>>> we would like to suggest a further simplification of the forest 
>>> structure. Specifically, we suggest that the work currently done on 
>>> the jdk9/hs-rt forest moves directly to the jdk9/hs forest. In 
>>> addition to making the forest structure easier to understand, this 
>>> would have the benefit of removing one set of integrations (jdk9/hs 
>>> <-> jdk9/hs-rt), which further reduces cost and propagation time. It 
>>> is also paving the way for eventually integrating up to jdk9/dev 
>>> more often (but that is a separate discussion).
>>>
>>> We suggest that the experiment starts on April 15th, and goes on for 
>>> at least two weeks (giving us some time to adapt in case of issues). 
>>> Monitoring and evaluation of the new structure will take place 
>>> continuously, with an option to revert back if things do not work 
>>> out. The experiment would keep going for at least a few months, 
>>> after which we will evaluate it and depending on the results 
>>> consider making it the new standard. If so, the jdk9/hs-rt forest 
>>> will eventually be retired, with an option of looking at further 
>>> reduction of forests going forward. At least for now, we suggest 
>>> that jdk9/hs-comp remains a separate forest and that it integrates 
>>> through jdk9/hs just like it does today.
>>>
>>> Much like when we merged the jdk9/hs-gc and jdk9/hs-rt forests we 
>>> would leave the jdk9/hs-rt forest around until we see if the 
>>> experiment works out. We would also lock it down so that no 
>>> accidental integrations are made to it. Once the jdk9/hs-rt forest 
>>> is locked down, any work in flight based on it would have to be 
>>> rebased on jdk9/hs.
>>>
>>> Please let us know if you have any feedback or questions!
>>>
>>> Cheers,
>>> Mikael
>>>
>>> [1]http://hg.openjdk.java.net/jdk9/hs-rt
>>> [2]http://hg.openjdk.java.net/jdk9/hs-comp
>>> [3]http://mail.openjdk.java.net/pipermail/hotspot-dev/2015-May/thread.html 
>>>
>>> [4]http://hg.openjdk.java.net/jdk9/hs-gc
>>> [5]http://hg.openjdk.java.net/jdk9/hs
>>> [6]http://hg.openjdk.java.net/jdk9/dev
>>>
>>
>