Re: [Xen-devel] RFC: change to 6 months release cycle

[George Dunlap <dunlapg@xxxxxxxxx>]

On Fri, Oct 2, 2015 at 6:43 PM, Wei Liu <wei.liu2@xxxxxxxxxx> wrote:
> Hi all
>
> As I understand it in the past there were discussions on release every
> 6 months. I would like to revisit this topic.
>
> # Rationale for a shorter release cycle
>
> The current 9 months cadence is too long. That create at least two
> problems for us.
>
> The first problem is that Xen delivers features much slower than other
> projects. Linux kernel releases every 3 months. QEMU releases every 4
> months. They deliver new features at a much higher frequency.
>
> The second problem is that the opportunity cost for vendors to miss a
> release is very high. When combined with the freeze exception scheme,
> tension quickly builds up around cut-off point, which creates
> frictions and frustrations for both contributors and maintainers. This
> is detrimental to the project in the long run.
>
> Having a shorter release cycle plus some other measures seem to make
> sense.
>
> The main objection from previous discussion seems to be that "shorter
> release cycle creates burdens for downstream projects". I couldn't
> quite get the idea, but I think we can figure out a way to sort that
> out once we know what exactly the burdens are.
>
> A side note is that if we really go down this route we need to stick
> with it for a few releases to let people get used to it. Any change to
> the release process is going to cause some issues.
>
> # Proposed release cycle
>
> Aim for 6 months release cycle -- 4 months development period, 2
> months hardening period. Make two releases per year.
>
> Fixed hard cut-off date, no more freeze exception. Arrange RCs
> immediately after cut-off.
>
> Take into account holiday seasons in US, Europe and China, the two
> cut-off dates are the Fridays in which that last day of March and
> September are in.
>
> Targeted release date is two months after cut-off date. Still, we pick
> a Friday using the same rule. We can also release a bit earlier if
> everything goes well. If we somehow fail to release on time, we eat
> into next development cycle. The next cut-off date will still be
> fixed.

+1

>
> With the proposed scheme, the dates will be:
>
>  - 4.7 cut-off date: April 1, 2016
>  - 4.7 release date: June 1, 2016
>
>  - 4.8 cut-off date: September 30, 2016
>  - 4.8 release date: December 2, 2016
>
>  - 4.9 cut-off date: March 31, 2017
>  - 4.9 release date: June 2, 2017

Won't that mean that 4.7 will essentially have a 9-month release again?

But the actual dates all look good -- hard cut-off more than 4 weeks
after any major holiday, release 3-4 weeks before any major holiday.
So we'll basically just have to wait until 4.8 to *actually* try the
6-month cycle thing.

I'm 100% on board with the "hard cut-off", but since we're dealing
with human beings, I think we should also include another target for
people to aim for.  We should tell people to *target* submissions for
at least 1 week, maybe 2, before the hard deadline.

So that would be:

4.7 submission target: 18 March 2016
4.7 cut-off: 1 April 2016
4.7 expected release: 1 June 2016

4.8 submission target: 16 September 2016
4.8 cut-off: 30 September 2016
4.8 expected release: 2 December, 2016

 -George

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