CFV: New Project: ZGC

Volker Simonis volker.simonis at
Fri Oct 27 09:29:38 UTC 2017

On Fri, Oct 27, 2017 at 10:56 AM, Aleksey Shipilev <shade at> wrote:
> On 10/27/2017 01:23 AM, John Rose wrote:
>> On Oct 26, 2017, at 8:42 AM, Volker Simonis <volker.simonis at> wrote:
>>> If no, why you propose ZGC at all and not contribute to
>>> Shenandoah? It's there since more than two years!  That you already
>>> worked on ZGC for some time as well doesn't count here because we (the
>>> OpenJDK community) couldn't see that and had no chance to contribute
>>> to it.
>> Put another way:  Would you really prefer that we keep ZGC
>> wraps while we replay the Shenandoah cross-examination, to
>> some s uggested number of months?  Wouldn't it be better to
>> get the code bases out there and then figure out what to do
>> with them?  Of course it would.
> Sure it would, and I am happy it happens! The inception of the project should not be blocked by the
> overlapping existing projects: show us the code, and all that, is in effect here. The same way
> anyone can do a Sandbox branch with whatever woozy idea that comes to mind, anyone with enough
> resources should be able to incept the project.
> It would of course be much nicer if ZGC was not developed under cover, so the community would have
> the opportunity to contribute, reconcile community roadmaps with its existence, and plan for adoption.
> What Volker taps into here, is the game-theoretical argument. The next big external contributor
> would face a dilemma: either it should invest heavily into the open project and get it out at its
> own expense, or it should patiently wait for Oracle to open its stash and contribute a similar
> project. The risk in doing the open-source project that runs into collision with late Oracle
> contribution is basically the opportunity cost for the contributor, which would make contributing
> less appealing. And the probability of such collision happening is non-ignorable, having at least
> two firm instances of this happening (AArch64 back then, and Shenandoah/ZGC today).
> Since we seem to agree there is no foul play on Oracle part here, and that we are dealing with the
> aftermath of Oracle closeness, this is less of an issue for Shenandoah. This might not be as true
> for the contributors after us who might think differently (after all, the prevalence of "Oracle is
> evil" mindset is astounding out there :/), without having the insights into project undercurrents.
> If we understand that we want the community around OpenJDK, we need to understand the late
> contributions like these -- however technically sound -- do have the social impact on the entire
> project. The successful open-source project is not exactly about pushing out the code, it is about
> the social dynamics that makes the large-scale community work possible. In my mind, it is important
> for at least Architects to recognize that, and accept Volker's concerns as legitimate. IMO, it would
> be enough at this point to accept that the past did suck, and we are dealing with its fallout, and
> would try to not get into this situation again.

I would be happy if that would be the outcome of my grumbling and
promise to hold my peace forever :)

> -Aleksey

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