Looking ahead: proposed Hg forest consolidation for JDK 10

[Staffan Larsen]

> On 13 Oct 2016, at 17:31, Andrew Hughes <gnu.andrew at redhat.com> wrote:
> 
> 
> 
> ----- Original Message -----
>> On 10/12/2016 9:25 AM, Andrew Hughes wrote:
>>> 
>>> ----- Original Message -----
>>>> snip...
>>>> 
>>>> 
>> 
>> [snip]
>> 
>>> Further to that, for OpenJDK 8, the relative repo sizes look like
>>> this (compressed):
>>> 
>>> -rw-r--r-- 1 andrew users 918K Aug  7 18:20 corba.tar.xz
>>> -rw-r--r-- 1 andrew users 6.5M Aug  7 18:22 hotspot.tar.xz
>>> -rw-r--r-- 1 andrew users 2.2M Aug  7 18:21 jaxp.tar.xz
>>> -rw-r--r-- 1 andrew users 2.2M Aug  7 18:21 jaxws.tar.xz
>>> -rw-r--r-- 1 andrew users  38M Aug  7 18:23 jdk.tar.xz
>>> -rw-r--r-- 1 andrew users 2.0M Aug  7 18:21 langtools.tar.xz
>>> -rw-r--r-- 1 andrew users 2.2M Aug  7 18:25 nashorn.tar.xz
>>> -rw-r--r-- 1 andrew users 327K Aug  7 18:20 openjdk.tar.xz
>>> 
>>> The JDK repository, even compressed, is over five times the size
>>> of HotSpot. Adding the other repos into the JDK repository thus
>>> wouldn't make that much of a difference to it, even if HotSpot is
>>> included, whereas it will cause an order of magnitude increase compared
>>> to the current side of the HotSpot repositories.
>>> 
>>> I think I'd thus prefer to see it cut down to two repositories. That
>>> would give most of the benefits I described of getting rid of all
>>> the superfluous repos, without bloating the requirements for HotSpot work.
>> 
>> Of course a consequence of a hotspot + everything else arrangement be
>> perpetuating the current inability to make atomic HotSpot + JDK changes.
>> 
> 
> Yeah, I'm aware of that. That's why I'm wondering what percentage of cross-repo
> commits include both HotSpot and some JDK repository. I do take on board the point
> made elsewhere that they become more likely if they are less problematic.

That percentage is probably small, but for some of us (particularly the group I am working in: serviceability), the percentage is very high.

> 
> I just think it's going to have a big impact for people working solely on HotSpot
> and so it needs to be clearly beneficial.

As Mikeal said in a different reply, all hotspot engineers within Oracle already work with a full forest since some months back. This has led to some changed workflows, but overall the feedback has been positive.

/Staffan

> 
>> Cheers,
>> 
>> -Joe
>> 
> 
> -- 
> Andrew :)
> 
> Senior Free Java Software Engineer
> Red Hat, Inc. (http://www.redhat.com <http://www.redhat.com/>)
> 
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