Re: [PATCH 2/2] tracing: add average time in function to function profiler

[Ingo Molnar <mingo@elte.hu>]

* Stephen Rothwell <sfr@canb.auug.org.au> wrote:

> Hi Steve,
> 
> On Wed, 25 Mar 2009 21:07:39 -0400 Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > From: Steven Rostedt <srostedt@redhat.com>
> > 
> > Show the average time in the function (Time / Hit)
> 
> Just wondering why we need to do this in the kernel ... there is 
> already enough information for a user to figure these averages 
> out.

Well, this argument can be applied to a lot of information exposed 
in /proc and /sys. For example in theory there's no need for 
/proc/interrupts at all, because the IRQ mappings are present in the 
syslog and in /sys enumerations and the IRQ counts are present in 
/proc/stat already.

I still find /proc/interrupts very handy, despite purist arguments 
that it is redundant and that it thus should not be there.

So we provide such things when it's easy to do, when it's a 
meaningful piece of information and it is convenient to users and 
developers.

Note that the function profiler is a double-non-default item in 
/debug (you need to enable two non-default options in the .config to 
get it), so you cannot stumble on it accidentally.

	Ingo