Re: [PATCH] ftrace: Add a C-state tracer to help poweroptimization

[Steven Rostedt]

On Sat, 4 Oct 2008, Arjan van de Ven wrote:

> On Fri, 3 Oct 2008 20:32:51 -0400 (EDT)
> Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> > > +struct trace_cstate {
> > > +	struct trace_entry	ent;
> > > +	struct cstate_trace	state_data;
> > > +};
> > > +
> > 
> > Can you please register this in the trace_assign_type macro.
> > 
> > 	IF_ASSIGN(var, ent, struct trace_cstate, TRACE_BOOT); \
> 
> I don't see this anywhere in the kernel ;(
> 
> > And here, do not typecast. Use the trace_assign_type macro below.
> 
> nor that guy

The two should be in linux-tip. If you are based against mainline, then
no they will not be.

If you are already using linux-tip, try refreshing.


> 
> 
> > 
> > > +	struct cstate_trace *it = &field->state_data;
> > > +	struct trace_seq *s = &iter->seq;
> > > +	struct timespec stamp = ktime_to_timespec(it->stamp);
> > 
> > Also note that iter->ts holds a timestamp counter from bootup in
> > nanosecs. It currently uses the sched_clock to record, but may change
> > later to something a bit better.
> 
> given that some of these clocks stop during idle... I really do care
> about which timestamp is used, tracing idle with a clock that stops
> during idle won't work too well.
> 

OK, I just wanted to let you know about it.

-- Steve

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