Re: [PATCH 0/11] LTTng-core (basic tracing infrastructure) 0.5.108

Ingo Molnar
2006-09-16T08:32:05Z

* Roman Zippel <zippel@linux-m68k.org> wrote:

> > > > Secondly, even people who intend to _eventually_ make use of
> > > > tracing, dont use it most of the time. So why should they have
> > > > more overhead when they are not tracing? Again: the point is not
> > > > moot because even though the user intends to use tracing, but
> > > > does not always want to trace.
> > >
> > > I've used kernels which included static tracing and the perfomance
> > > overhead is negligible for occasional use.
> >
> > how does this suddenly make my point, that "a marker for dynamic
> > tracing has lower performance impact than a static tracepoint, on
> > systems that are not being traced", "moot"?
>
> Why exactly is the point relevant in first place? How exactly is the
> added (minor!) overhead such a fundamental problem?

how could a fundamental performance difference between two markup
schemes be not relevant to kernel design decisions? Which performance
difference i claim derives straight from the conceptual difference
between the two approaches and is thus "unfixable" (and not an
"implementational issue").

Ingo