Re: [GIT PULL] tracing: make signal tracepoints more useful

From: Ingo Molnar
Date: Wed Jan 18 2012 - 04:40:09 EST



* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Mon, Jan 16, 2012 at 7:10 AM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
> >
> > But do we really need to keep the old tracepoint? IOW, what
> > if we simply rename it and add more info?
>
> Quite frankly, unless somebody can point to something that
> breaks, I'd rather just change the existing one.
>
> Nobody outside of a few special cases uses tracepoints.
> *nobody*. The only apps I have ever seen that matters to
> anybody ends up being latencytop and powertop. If those two
> have been tested and don't care, I don't think we should care.

Correct. (There's also sysprof and perf - both should be fine.)

As i said in my very first mail:

> [...] Which apps/tools rely on the old tracepoint? If it's
> exactly zero apps then we might be able to change it, but this
> needs to be investigated.

I resisted Steve's "this ABI change is safe by design" notion
which is somewhat of a disease. It is probably fine but not by
definition.

Thanks,

Ingo
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