Re: next steps

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

Hi -

On Mon, Sep 26, 2005 at 10:11:01AM -0500, Jose R. Santos wrote:

> [...]  one of the requirements that the tool need is that for every
> probe inserted, the cpu, pid, tid and a time-stamp (jiffies?) be
> returned as well as some additional information that would be probe
> specific.

function ln /* labeled number */ (name, value) {
  print (name . "=" . string(value) . " ")
}
function trace_common_stuff () {
  ln ("cpu", cpu()) # cpu() to go into context tapset
  ln ("pid", pid()) 
  ln ("jiffies", jiffies()))  # jiffies() to go into in timestamp tapset
}
probe THIS, THAT { 
  trace_common_stuff ()
  print ("probe specific\n")
}
probe OTHER {
  trace_common_stuff ()
  print ("other probe specific\n")
}

> While it is possible to grab all these using SystemTap, I wonder if
> it would make more sense to have a special trace probe that does all
> this and then have SystemTap exploit this. [...]

Perhaps the confusion is one of terminology.  A "trace probe" is not a
thing with an obvious meaning.  Using plain systemtap script pieces
like the one above can likely get you what you need.


- FChE