Re: [PATCH] ftrace: add an fsync tracer

["Frank Ch. Eigler" <fche@redhat.com>]

Hi -

On Thu, Nov 06, 2008 at 09:29:03PM +0100, Peter Zijlstra wrote:
> [...]
> I prefer we keep using trace points but do what jason has been proposing
> for a while, which is add a format and arg list to the trace point
> definition.
> 
> Something like
> 
> DEFINE_TRACE_FMT(sched_switch,
> 	TPPROTO(struct rq *rq, struct task_struct *prev,
> 		 struct task_struct *next),
> 	TPARGS(rq, prev, next),
> 	TPFMT("%d to %d\n", prev->pid, next->pid));
> 
> Which would be similar to attaching a trace_mark() to the trace point
> and can in these cases save a lot of lines of code.

Can you explain how this would save any lines of code at all compared
to the trace_mark() example?  Both cases still need a bit of
~identical additional code to couple the markers (specified whichever
way) to a trace buffer.  Your version has the tracepoint machinery
too, which is strictly additional.  Where's the savings?


- FChE