Re: [RFC PATCH v1 0/2] perf: Support for SDT markers

[Hemant Kumar]

On 02/26/2014 01:48 PM, Namhyung Kim wrote:
> Hi Masami and Hemant,
>
> On Tue, 25 Feb 2014 21:27:07 +0530, Hemant Kumar wrote:
> > On 02/25/2014 05:14 PM, Masami Hiramatsu wrote:
> > > (2014/02/24 18:14), Hemant Kumar wrote:
> > > > First, scan the binaries using :
> > > > # perf list sdt --scan
> > > >
> > > > Creating a cache of SDT markers...
> > > > perf sdt cache created!
> > > >    Use : "perf list sdt"
> > > >    to see the SDT markers
> > > Hmm, in that case, I think you'd better introduce perf-sdt for scanning.
> > > e.g.
> > >
> > >    # perf sdt --scan app
> > Hmm, this seems a better idea :)
> >
> > >    then you can add app to sdt cache, without app,
> > >
> > >    # perf sdt --scan
> > >
> > >    will just scans all binaries on the PATH and the libraries which listed
> > > by `ldconfig --print-caceh`
> What should be done with the new perf sdt command?  If it's only
> intended to list the markers, I'd just suggest to add "perf list sdt" as
> this patch did.

If we display the SDT markers along with the other events in perf list, 
then I think we can go with
perf list sdt. I am not too sure though! :)

For me, the main issue was that the markers are not events. They become 
events after
we place them in the uprobe_events file just like functions.  But we use 
`perf list` to
display all the "events" available on a system. Isn't it?

> Plus I think it'd be better if event_glob pattern also looks for sdt
> markers so that user can find out a specific markers easily, e.g.:
>
>    # perf list rtld:*
>
> or
>
>    # perf list %rtld:*

Good idea! Will surely include support for this in event_glob pattern.

> > > And perf-list shows only the SDTs in the cache.
> > Well, what will be better? perf-list or perf-sdt or perf-list sdt??
> > If perf-list, then wouldn't it be a huge list!!
> The output of perf list is already a huge list and we paginate it.  So I
> don't think it's gonna be a problem. :)

Ok! Then we can use perf list. :)

> > > > - Add support to probe these SDT markers and integrate with a previous patch
> > > >     (support to perf to probe SDT markers) posted in lkml.
> > > >     https://lkml.org/lkml/2013/10/23/10
> > > Yeah, but I think we'd better choose another way to integrate it.
> > > Since SDT is like markers(static events), setting each of them via perf-probe is
> > > not intuitive. :)  I'd like to use it as an event, e.g.
> > >
> > >    # perf top -e "%libgcc:unwind"
> > >
> > > And perf top internally calls perf-probe to add new uprobe event, and
> > > clean the new event at exit.
> > Yeah! Right :) Makes sense.
> >
> > Will implement the suggestions in the next version asap!
> That would be great!

--
Thanks
Hemant Kumar

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/