Re: [PATCH] x86: add the debugfs interface for the sysprof tool

[Andrew Morton <akpm@linux-foundation.org>]

On Sat, 23 Feb 2008 12:37:24 +0100 Ingo Molnar <mingo@elte.hu> wrote:

> * Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> > > Sysprof needs a 200 line kernel module to do it's work, this module 
> > > puts some simple profiling data into debugfs.
> > > 
> > > ...
> > 
> > Seems a poor idea to me.  Sure, oprofile is "hard to set up", but not 
> > if your distributor already did it for you.
> 
> two things.
> 
> Firstly, this isnt an oprofile replacement, this is a pretty separate 
> concept. Sysprof is more of a tracer than a profiler.

I don't understand the distinction and I don't see what sysprof (as defined
by its kernel->userspace interface) can do which oprofile cannot.

This is yet another thing which should have been in the damned changlog but
wasn't.

> (and we are 
> currently working on merging it into ftrace)

I think you should drop it and we should see a replacement patch which has
all the bugs, inefficiencies and deficiencies addressed and which has a
vaguely respectable description.

> Secondly, real developers who tune user-space code disagree with your 
> characterisation of oprofile being easy to use.

afacit all of these criticisms surround oprofile's userspace tools only.