Re: [lttng-dev] [PATCH 09/11] sched: export task_prio to GPL modules

Frank Rowand
2011-12-20T21:47:04Z

On 12/20/11 03:08, Ingo Molnar wrote:
>
> (Cc:-ing Arnaldo on this as well.)
>
> * Mathieu Desnoyers <compudj@krystal.dyndns.org> wrote:
>

< snip >

> I think your concentration on ABIs is missing a very fundamental
> property of instrumentation:
>
> the life-time and persistence of instrumentation data is
> typically very short ('days' is already an exception - typical
> is minutes, at most hours), and for that reason we havent been
> getting much pressure from users to maintain a perf.data ABI -
> but we are doing it nevertheless.
>
> Instrumentation is fundamentally about the 'here and now' and so
> it fundamentally differs from things like backup formats and
> database formats. An ABI does not hurt and we are maintaining
> it, but you are overrating its importance significantly.

Just to provide visibility to a different use case...

The life time of my data is typically weeks, months, or years
(though I am not likely to re-process year old raw data).

< snip >

-Frank