Re: [PATCH 2/4] tracing: add event trace infrastructure

[Ingo Molnar <mingo@elte.hu>]

* Andrew Morton <akpm@linux-foundation.org> wrote:

> On Tue, 24 Feb 2009 23:08:56 -0500 (EST) Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> > > Gad, what a lot of stuff.
> > > 
> > > Use strncpy_from_user()?
> > > 
> > > Use strstrip()?
> > > 
> > > Why do we care about leading and trailing whitespace - user error!
> > 
> > This is because i want:
> > 
> >  cat available_events > set_event
> > 
> > to work.
> 
> :(
> 
> Why on earth do we keep on putting all these pretty-printers 
> and pretty-parsers into the kernel?  I mean, how hard is it 
> for userspace to read a text file, do some basic substitutions 
> and print it out again?

Note that there's no mandatory user-space component here - the 
final destination is the kernel developer's eyes in 90% of the 
cases. These traces get pasted into email, etc. etc.

So leading spaces, meaningful formatting and general hands-on 
usability is important. [ I know, it's a strange concept in the 
kernel, we tend to have a perversion for the most unusable and 
most inconsistent user interfaces ;-) ]

It's also a balancing act. We dont want to put all of TeX into 
the kernel obviously. Nor do we want the default to be the 
opposite end of the spectrum: to output raw binary records. So 
we find some middle ground. That middle ground is inluenced by 
the developers using this stuff.

	Ingo