proposal - dissolve the OpenJDK hsx Project after jdk8 ships

[Kirk Pepperdine]

Hi John,

I don't get to vote but it seems sensible to couple a version of HotSpot to a version of the JDK.
 
----
Kirk Pepperdine
On Dec 10, 2013, at 10:02 PM, John Coomes <John.Coomes at oracle.com> wrote:

> The hsx Project was created to make hotspot development independent of
> specific JDK releases, so the same source could then delivered into
> multiple JDK releases simultaneously.  This has worked pretty well for
> a number of years, allowing us to get significant features and
> performance improvements into shipping, supported JDK releases much
> more quickly.
> 
> However, it has also complicated hotspot development in several ways.
> We have to maintain compatibility with multiple JDK
> releases--supporting old operating systems, old tool chains and old
> JDK APIs.  It is also more difficult to make large-scale or behavioral
> changes, since delivering into update releases requires a high degree
> of compatibility and allows only a relatively short time for
> stabilization.  And there is also the overhead of a separate OpenJDK
> Project, separate version tracking in the bug database and the mental
> overhead of having to map a hotspot version to/from a jdk version.
> 
> Further, because of compatibility concerns, we have not delivered the
> same source into multiple JDK releases for more than 18 months,
> incurring the costs without reaping the benefits.  So I propose that
> the hsx Project be dissolved after jdk8 has shipped, and that hotspot
> development move to be more closely aligned with future JDK releases.
> 
> In practical terms this means that:
> 
> 	- the general process for delivering hotspot into jdk8 will
> 	not change, to avoid disruption late in the release cycle.
> 	The remaining critical fixes needed for jdk8 will continue to
> 	be made in the existing hsx repos.
> 
> 	- as the number of expected jdk8 fixes decreases to a trickle,
> 	jdk8 development and testing should move from the hsx group
> 	repos (e.g., hotspot-gc, hotspot-rt, etc.) to a single
> 	stabilization repo (possibly hsx/hotspot-main).  Alejandro
> 	Murillo, the hotspot gatekeeper, will coordinate this.
> 
> 	- hsx Project Author/Committer/Reviewer status will be
> 	transferred to the new jdk9 [1] [2] and jdk8u [3] [4]
> 	Projects.
> 
> 	- the bulk of hotspot development will take place in new repos
> 	that are part of the jdk9 project (e.g.,
> 	http://hg.openjdk.java.net/jdk9/hotspot-gc,
> 	http://hg.openjdk.java.net/jdk9/hotspot-comp, etc.)
> 
> 	- bug fixes appropriate for jdk8 update releases will have to
> 	be selected and backported individually.  I anticipate that a
> 	new jdk8 update tree for hotspot will be created (name tbd),
> 	so that we can continue to do pre-integration testing and bulk
> 	integrations as we have done for jdk7 updates.
> 
> 	- hotspot bugs for jdk9 and jdk8 updates will be tracked in
> 	JBS using the jdk version number, not a separate hotspot
> 	version number (e.g., we'll use '9' or '8u20' instead of
> 	'hs26' or 'hs25.20').
> 
> 	- after the last hotspot bug fix has been delivered to jdk8,
> 	the hsx Project repos will become read-only and maintained
> 	simply for archival purposes.
> 
> Apologies for the length of this messages; I'm hoping to answer the
> obvious questions in advance.  Please follow up if you have comments
> or if there are any I missed.
> 
> -John
> 
> [1] http://mail.openjdk.java.net/pipermail/announce/2013-October/000155.html
> [2] http://mail.openjdk.java.net/pipermail/announce/2013-November/000156.html
> [3] http://mail.openjdk.java.net/pipermail/announce/2013-December/000157.html
> [4] http://mail.openjdk.java.net/pipermail/discuss/2013-December/thread.html