lkml.org 
[lkml]   [2009]   [Aug]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: system gets stuck in a lock during boot
From
Date
On Mon, 2009-08-24 at 14:13 +0800, Li Zefan wrote:
> Peter Zijlstra wrote:
> > On Mon, 2009-08-24 at 10:41 +0800, Li Zefan wrote:
> >
> >>> @@ -940,7 +940,7 @@ event_create_dir(struct ftrace_event_call *call, struct dentr
> >>> entry = trace_create_file("enable", 0644, call->dir, call,
> >>> enable);
> >>>
> >>> - if (call->id)
> >>> + if (call->id && call->profile_enable)
> >> We do an extra check on ->profile_enable, shouldn't cause bug..
> >>
> >>> entry = trace_create_file("id", 0444, call->dir, call,
> >>> id);
> >> Any way, I don't think this commit does the right thing:
> >>
> >> - If CONFIG_EVENT_PROFILE=y, we'll create events/<dir>/<event>/id,
> >> except events/ftrace/<event>/id.
> >>
> >> - if CONFIG_EVENT_PROFILE=n, there's no 'id' file at all!
> >>
> >> I think it's better to skip ftrace/ dir in perf tool code, instead of
> >> skipping creating id files in ftrace code.
> >
> > No, it does do the right thing. Your patch breaks things because not all
> > tracepoints are created through TRACE_EVENT() and will thus not have
> > their profile_enable/disable hooks set.
> >
> > By giving them an ID file, there is no way to distinguish good from bad
> > tracepoints.
> >
>
> But removing the id file from events/ftrace/ might break some ftrace
> binary parsers?
>
> And this commit makes 'id' file disapeared with CONFIG_EVENT_PROFILE=n.

I introduced the id file for EVENT_PROFILE, tough luck if someone else
relies on it.

> > Expempting ftrace is no solid solution, suppose someone else does a
> > TRACE_EVENT_FORMAT() tracepoint, how would you know you could use it as
> > a profile event source?
> >
>
> Agree.
>
> > The id files really must stay conditional.
> >
>
> I don't think it's a good idea to connect it with perfcounter
> this way. Wouldn't adding a 'profilable' file more intuitive?

its called: id ;-)


\
 
 \ /
  Last update: 2009-08-24 08:59    [from the cache]
©2003-2011 Jasper Spaans