Hotspot shell games

[Andrew John Hughes]

2009/5/29 Kelly O'Hair <Kelly.Ohair at sun.com>:
>
> (removed jdk7-dev from this discussion)
>
> Andrew John Hughes wrote:
>>
>> 2009/5/29 Erik Trimble <Erik.Trimble at sun.com>:
>
> [snip]
>>>
>>> For now, though, we need to decide how to handle HSX vs Open6 vs. IceTea.
>>
>> Simplest solution would be to just remove it from OpenJDK6 and use HSX
>> as the upstream.  I don't see an advantage to pulling in to OpenJDK6,
>> given there is already a 'stable' branch of HSX.
>
> I would prefer to keep a hotspot repository in the openjdk6 forest, just
> for the sake of having a buildable and complete source base.

I can see the advantage, though I would guess the number of people
doing OpenJDK6 builds is far smaller than those doing IcedTea builds
which has been deleting the OpenJDK6 repo and replacing it for months
now.  If the OpenJDK6 repo is again allowed to bit-rot, then we're
likely to have to do this again.  We'd obviously prefer to be working
on a common upstream rather than having effectively two communities.

> I would also like to have some level of confidence as to which hotspot
> is the default one for the openjdk6 project.
> Let's not leave a partial jdk6 forest sitting out there.
>

My main concern is maintenance.  If what is there is maintained
regularly, I don't care too much either way.  That said, I'd prefer to
see less duplication though, and this also extends to CORBA, JAXP and
JAXWS as Joe already mentioned.

> To me the decision that needs to be made is whether you want the
> openjdk6 hotspot repository (jdk6/hotspot) 'related' to the other
> hotspot repositories, like hsx/hsx14/master is related to jdk7/hotspot.

It isn't related; hsx includes several build drops that were never in
the public HotSpot repositories and which we had to wait over three
months for.

> It doesn't have to be, and there are advantages and disadvantages to
> both approaches.
> None of the non-hotspot repositories in the openjdk6 forest are related
> to the jdk7 repositories, making them pretty independent from jdk7,

Which is sensible, given 6 has to be stable.  It being based off jdk7
is merely an issue of when things were released under the GPL, as I
believe you or Joe have blogged about before.

> but hotspot is somewhat special, and the express model I support, so...
>
> My suggestions...
>  * Ignore hsx/hsx14, it's a drop not a development tree

What??? I don't believe any discussions around HSX ever being about it
being just a drop.  It's meant to be a stability branch of hs14 for
use in OpenJDK6 and Sun's JDK6 releases.  If it was a drop, why do a
forest at all and not just update OpenJDK6?

>  * Decide to make the jdk6 and jdk7 repositories 'related'

Impossible, unless I misunderstand what you mean by 'related'.

>  * Tag the rev in the jdk7/hotspot repo with a name jdk6-b17, the
>    rev that matches what is in the hsx14 repo

Again there is no hs14b11...hs14b16 in the public HotSpot repository.
That's what sparked the whole discussion that lead to HSX in the first
place.  Sun took HotSpot 14 'underground' and out of the public eye as
regards further stability work.  With hsx, we finally seem to have
reversed this process by the release of hs14b11...hs14b16 and I'd
expect to see further releases appear there too.

>  * Toss the existing jdk6/hotspot repo and replace it with a repo
>    created with:
>        hg clone -r jdk6-b17 http://hg.openjdk.java.net/jdk7/hotspot
> jdk6/hotspot
>

I think the only options are to pull in changeset 0 from hsx to rebase
the HotSpot repo on that, or (simpler) replace it with a clone of hsx.
 The former would preserve the commit history and would be more useful
over time IMO.

> Changes going into jdk6/hotspot should be rare, critical, and should
> eventually be pushed back into jdk7/hotspot, indeed some critical fixes
> may get transplanted from jdk7/hotspot to jdk6/hotspot.
> If at some point it's decided to upgrade jdk6/hotspot to a newer rev,
> so be it, easy to do.
>

I think changes should just go to hsx and then feed into OpenJDK6
through regular pulls, if we plan to maintain a repo. there.

> And for heavens sake, start adding some hsx-* tags to the hotspot repository
> so we can easily clone hsx versions from the tag name, you could also use
> the hsx tag to hold the build number, I can help with that.
>

Now this I agree on :)

> -kto
>
>
>



-- 
Andrew :-)

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Red Hat, Inc. (http://www.redhat.com)

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