Re: [RFC PATCHSET] sched,perf: unify tracers in sched and move perf on top of TP

Peter Zijlstra
2010-05-06T07:04:36Z

On Thu, 2010-05-06 at 08:31 +0200, Ingo Molnar wrote:
> * Peter Zijlstra <peterz@infradead.org> wrote:
>
> > Well, I'd much rather just see a direct call in the code than having to
> > reverse engineer wth hangs onto that _EVENT() junk.
>
> Direct calls into code were fine 10 years ago, but since then we got:
>
> - preempt notifiers

Are per task an no good for driving perf.

> - sw events
> - tracepoints

Are unrelated to the core perf scheduler calls.

> Which add up to a lot more than just a plain call into code.
>
> Also, with the jump-optimizations we will have tracepoints that are _cheaper_
> than a plain function call.

Which can just as easily be used on the core perf hooks.

> > Also, we don't need ABI muck for this.
>
> we already have an ABIs in place here - this would just properly unify and
> enumerate it.

I'm not getting it, this is about in-kernel stuff, there are _NO_ in
kernel ABIs.