Re: [PATCH v1 0/5] perf/sdt: SDT events listing/probing

[Hemant Kumar <hemant at linux dot vnet dot ibm dot com>]

Hi Masami,

On 10/01/2014 09:38 PM, Masami Hiramatsu wrote:
> Hi,
>
> (2014/10/01 0:29), Hemant Kumar wrote:
> > This patchset helps in listing dtrace style markers(SDT) present in user space
> > applications through perf.
> > Notes/markers are placed at important places by the
> > developers. They have a negligible overhead when not enabled.
> > We can enable them and probe at these places and find some important information
> > like the arguments' values, etc.
> >
> > We have lots of applications which use SDT markers today, like:
> > Postgresql, MySql, Mozilla, Perl, Python, Java, Ruby, libvirt, QEMU, glib
> >
> > To add SDT markers into user applications:
> > We need to have this header sys/sdt.h present.
> > sys/sdt.h used is version 3.
> > If not present, install systemtap-sdt-devel package (for fedora-20).
> >
> > With this patchset,
> > - Use perf sdt-cache --add to add SDT events to a cache.
> >   # perf sdt-cache --add ./user_app
> >
> >    4 SDT events added for /home/user/user_app!
> >
> > - Use perf sdt-cache --del to remove SDT events from the cache>
> >   # perf sdt-cache --del ./user_app
> >
> >   4 events removed for /home/user/user_app!
> >
> > - Dump the cache onto stdout using perf sdt-cache --dump:
> >   # perf sdt-cache --dump
> >    /home/user/user_app :
> >    %user_app:foo_start
> >    %user_app:fun_start
> >
> > - To probe and trace an SDT event :
> >    # perf record -e %user_app:foo_start -aR sleep 10
> Looks great! :)

Thankyou :)

> However, when I've tried to build, I got below errors..
>
>    CC       util/sdt.o
> util/sdt.c: In function âsdt_errâ:
> util/sdt.c:72:3: error: implicit declaration of function âpr_errâ [-Werror=implicit-function-declaration]
>     pr_err("%s: No SDT events found\n", target);
>     ^
> util/sdt.c:72:3: error: nested extern declaration of âpr_errâ [-Werror=nested-externs]
> util/sdt.c: In function âfile_hash_list__initâ:
> util/sdt.c:489:3: error: implicit declaration of function âpr_debugâ [-Werror=implicit-function-declaration]
>     pr_debug("Error in madvise\n");
>     ^
> util/sdt.c:489:3: error: nested extern declaration of âpr_debugâ [-Werror=nested-externs]
> cc1: all warnings being treated as errors
>
> Perhaps, you might working on the old tree. Could you update it?

Hmm. Yes, it was on an older tree. Will update it and repost them.

> [SNIP]

--
Thanks,
Hemant Kumar