DTrace probes & klds

[Daniel O'Connor]

On Fri, 21 Aug 2009, Alexander Leidinger wrote:
> Quoting Daniel O'Connor <doconnor at gsoft.com.au> (from Thu, 20 Aug
> 2009
>
> 17:13:07 +0930):
> > On Thu, 20 Aug 2009, Alexander Leidinger wrote:
> >> Quoting Daniel O'Connor <doconnor at gsoft.com.au> (from Wed, 19 Aug
> >> 2009
> >>
> >> 23:31:33 +0930):
> >> > Content-Type: text/plain;
> >> >   charset="utf-8"
> >> > Content-Transfer-Encoding: quoted-printable
> >> > Content-Disposition: inline
> >> >
> >> > Is it possible? the handbook implies not and I can't get it to
> >> > work, but i could be doing it wrong..
> >> >
> >> > I get fbt traces listed for KLDs (I get new entries for each
> >> > load of the KLD which seems like a potential problem) but I
> >> > can't specify an SDT_PROBE and have it work.
> >>
> >> Can you show us some example code?
> >
> > /* Recycle fbt as SDT_PROVIDER_DEFINE is said not to work */
> > SDT_PROBE_DEFINE(fbt, gsio, gsio_intr, test);
> > SDT_PROBE_ARGTYPE(fbt, gsio, gsio_intr, test, 0, "int");
> > SDT_PROBE_ARGTYPE(fbt, gsio, gsio_intr, test, 1, "int");
>
> I don't think you can define a fbt probe by hand. You can define a
> provider on your own via SDT_PROVIDER_DEFINE (in only one
> place/file), and then use this provider instead of fbt above. Let's
> assume you defined a gsio provider, then the SDT_PROBE_DEFINE could
> be
>    SDT_PROBE_DEFINE(gsio, <unique_part_of_name_of_file>, gsio_intr,
> test);

Yes, I only wanted to reuse fbt because the handbook says 
SDT_PROBE_DEFINE doesn't work as a KLD.

> If there's only one file, it does not make much sense to add an
> unique part of the name of the file, but if you have multiple files
> it can be helpful. But this is just an example, for example in GEOM
> it would make sense to name the provider "geom", and instead of the
> file name use the module name, e.g. mirror, raid3, core/whatever, ...
> instead.

Hmmm. I have tried that, but not joy :(

SDT_PROVIDER_DEFINE(gsio);
SDT_PROBE_DEFINE(gsio, main, gsio_intr, test);
SDT_PROBE_ARGTYPE(gsio, main, gsio_intr, test, 0, "int");
SDT_PROBE_ARGTYPE(gsio, main, gsio_intr, test, 1, "int");
...
        SDT_PROBE(gsio, main, gsio_intr, test, istat, 0, 0, 0, 0);


I built my module with WITH_CTF=1 and I see that ctfconvert is run, 
however when I load it the Dtrace providers/providers aren't there.

Building it into the kernel works but isn't ideal.

Hmm, initially I was building my KLD outside of the tree, however when I 
build it with buildkernel & load it dtrace -l crashes the system and I 
can't get a crashdump at the moment.. I'll try again when I can get to 
the console.

-- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 188 bytes
Desc: This is a digitally signed message part.
Url : http://lists.freebsd.org/pipermail/freebsd-hackers/attachments/20090822/83c5bad7/attachment.pgp