Re: Scalable Event Channel ABI design (draft A)

[George Dunlap <george.dunlap@eu.citrix.com>]

On 05/02/13 18:57, David Vrabel wrote:
> What to do here is a non-trivial decision.  Possible options include:
>
> 1. Merge the 3-level ABI for 4.3.  Work on the FIFO-based ABI in
> parallel, aiming to get this in for 4.4.  This means maintaining 3 event
> channel ABIs in Xen.
>
> 2. Slip the 4.3 release for 2-3 months and merge the FIFO-based ABI in.
>
> 3. Status quo.  Defer extending the event channel ABI to 4.4.
>
> The preferable option may be to:
>
> 4. Get the 3-level ABI to a mergable state. In parallel develop a
> prototype of the FIFO-based ABI.  When the prototype is ready or the 4.3
> freeze is here, evaluate it and make a decision then.

Just to clarify, the difference between #1 and #4 is that in #4 we hold 
off on the merge, to delay committing to a specific course of action 
until later?

That seems at first blush to be a pretty safe option.  But I think it's 
worth pointing out that in practice the end result is likely to be that 
we just go with #1 eventually anyway: if the FIFO ABI can't be finished 
in 4 months giving it all our effort, can we really expect it to be 
finished in any less time while polishing up the 3-level ABI?

I was going to say, "There's no particular reason to merge the 3-level 
ABI sooner rather than later", but of course there is: it allows 
considerably longer and wider testing.

No conclusion here, just adding to the mix of things to consider. :-)

  -George