Re: [PATCH -v5 08/11] tracing: not trace mips_timecounter_init() in MIPS

Wu Zhangjin
2009-11-03T01:34:20Z

Hi,

On Mon, 2009-11-02 at 22:43 +0100, Frederic Weisbecker wrote:
[...]
> > > > -static inline u64 mips_timecounter_read(void)
> > > > +static inline u64 notrace mips_timecounter_read(void)
> > >
> > >
> > > You don't need to set notrace functions, unless their addresses
> > > are referenced somewhere, which unfortunately might happen
> > > for some functions but this is rare.
> > >
> >
> > Okay, Will remove it.
>
>
>
> Oops, a word has escaped from my above sentence. I wanted to say:
>
> "You don't need to set notrace to inline functions" :)
>
>

Thanks ;)

I have got your meaning at that time, and have removed them with inline
functions.

> > > But I would rather see a __mips_notrace on these two core functions.
> >
> > What about this: __arch_notrace? If the arch need this, define it,
> > otherwise, ignore it! if only graph tracer need it, define it in "#ifdef
> > CONFIG_FUNCTION_GRAPH_TRACER ... #endif".
>
> The problem is that archs may want to disable tracing on different
> places.
> For example mips wants to disable tracing in timecounter_read_delta,
> but another arch may want to disable tracing somewhere else.
>
> We'll then have several unrelated __arch_notrace. One that is relevant
> for mips, another that is relevant for arch_foo, but all of them will
> apply for all arch that have defined a __arch_notrace.
>
> It's true that __mips_notrace is not very elegant as it looks like
> a specific arch annotation intruder.
>
> But at least that gives us a per arch filter granularity.
>
> If only static ftrace could disappear, we could keep only dynamic
> ftrace and we would then be able to filter dynamically.
> But I'm not sure it's a good idea for archs integration.
>

Got it.

Thanks & Regards,
Wu Zhangjin