* Arjan van de Ven <[email protected]> wrote:
> On 10/19/2010 4:52 AM, Ingo Molnar wrote:
> >* Peter Zijlstra<[email protected]> wrote:
> >
> >>On Tue, 2010-10-19 at 13:45 +0200, Ingo Molnar wrote:
> >>>* Thomas Renninger<[email protected]> wrote:
> >>>
> >>>>>Most definitely. It's no accident that it took such a long time for this
> >>>>>issue
> >>>>>to be raised in the first place. It's a rare occurance -
> >>>>Do you agree that this occurance happened now and these events should get
> >>>>cleaned
> >>>>up before ARM and other archs make use of the broken interface?
> >>>>
> >>>>If not, discussing this further, is a big waste of time... and Jean would
> >>>>have to
> >>>>try to adapt his ARM code on the broken ABI...
> >>>The discussion seems to have died down somewhat. Please re-send to lkml
> >>>the latest
> >>>patches you have to remind everyone of the latest state of things - the
> >>>merge window
> >>>is getting near.
> >>>
> >>>My only compatibility/ABI point is basically that it shouldnt break
> >>>_existing_
> >>>tracepoints (and users thereof). If your latest bits meet that then it
> >>>ought to be a
> >>>good first step. You are free to (and encouraged to) introduce more
> >>>complete sets of
> >>>events.
> >>Can we deprecate and eventually remove the old ones, or will we be forever
> >>obliged
> >>to carry the old ones too?
> >We most definitely want to deprecate and remove the old ones - but we want
> >to give
> >instrumentation software some migration time for that.
> >
> >Jean, Arjan, what would be a feasible and practical deprecation period for
> >that? One
> >kernel cycle?
>
> more like a year
>
> for some time software needs to support both, especially if popular distros
> stick
> to an older kernel like *cough* RHEL6
Sure, you can support both. But as long as support for the _new_ events is
included
in PowerTop there's no need to keep the duality upstream. Running ancient
PowerTop
on fresh kernels is not common.
An old RHEL kernel will still keep on working as you can keep support for old
events
in PowerTop as long as you wish to.
The new kernel also wont 'overwrite' old events with new definitions in the
future,
so PowerTop will keep working for as long as you want to support older kernels.
Does that sound good?
Thanks,
Ingo
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