Re: Sample based profiling

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Sun, Aug 05, 2018 at 12:22:04AM +0200, Joerg Sonnenberger wrote:
> On Thu, Aug 02, 2018 at 09:26:00PM -0400, Thor Lancelot Simon wrote:
> > On Thu, Aug 02, 2018 at 01:46:35PM +0200, Joerg Sonnenberger wrote:
> > > On Wed, Aug 01, 2018 at 11:54:10PM -0400, Thor Lancelot Simon wrote:
> > > > On Tue, Jul 31, 2018 at 08:28:19AM +0000, Christos Zoulas wrote:
> > > > > In article <2c408f23-6eae-da00-dfb2-ebc7b66e689c%gmx.com@localhost>,
> > > > > Kamil Rytarowski  <n54%gmx.com@localhost> wrote:
> > > > > >
> > > > > >I'm for removal of gprof and deduplication of .a files in the base.
> > > > > >
> > > > > >While there, can we get rid of moncontrol(3), profil(2) and all the
> > > > > >corresponding code?
> > > > > 
> > > > > I constantly see proposals to remove things from base without replacing
> > > > > the functionality first. Yes, the current state is poor but the 
> > > > > "hand hurts, cut hand" approach is worse.
> > > > 
> > > > Here it'd also be "cut arm", I think, since the kernel profiling that
> > > > relies on the same tools does still work, and, though limited, can do
> > > > some things out of the box that take nontrivial effort with the DTrace
> > > > FBT provider, the nearest alternative.
> > > 
> > > The kernel is quite different beast as it is self-contained.
> > 
> > But it uses the same userspace tools for analysis.
> 
> I haven't been talking about gprof, I could care less about that
> program itself. That said, I would expect copying the interceptor

Oh, FFS.  Please read the *very first line quoted above*.

I don't care whether you rip out -pg support for userland so long as you
say there's a better alternative - I trust you.  But, please. don't
touch tools shared with the kernel profiling unless and until there is
a fully equivalent and documented alternative in our source tree.

-- 
 Thor Lancelot Simon	                                     tls%panix.com@localhost
  "Whether or not there's hope for change is not the question.  If you
   want to be a free person, you don't stand up for human rights because
   it will work, but because it is right."	--Andrei Sakharov