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Subject: Re: [PATCH 2/3] perf build: Use libtraceevent from the system
From:   Athira Rajeev <atrajeev@linux.vnet.ibm.com>
In-Reply-To: <Y498YP2N3gvFSr/X@kernel.org>
Date:   Wed, 7 Dec 2022 19:08:28 +0530
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-perf-users@vger.kernel.org, bpf@vger.kernel.org,
        Stephane Eranian <eranian@google.com>
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Message-Id: <C9F248C8-AF8D-40A1-A1AD-BCC39FBA01C7@linux.vnet.ibm.com>
References: <20221205225940.3079667-3-irogers@google.com>
 <Y49qiCIiyaehEOaG@kernel.org> <Y49rvLO2RnJBBNL/@kernel.org>
 <Y49skYa5VYPMU+RF@kernel.org> <Y49uKfzfCoZ1ok62@kernel.org>
 <Y49vx0v6Z7EiR8jr@kernel.org> <Y49wxSIK7dJ7iTDg@kernel.org>
 <Y491d1wEW4TfUi5f@kernel.org> <Y4921D+36UGdhK92@kernel.org>
 <Y494TNa0ZyPH9YSD@kernel.org> <Y498YP2N3gvFSr/X@kernel.org>
To:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Ian Rogers <irogers@google.com>
Precedence: bulk


> On 06-Dec-2022, at 11:01 PM, Arnaldo Carvalho de Melo =
<acme@kernel.org> wrote:
>=20
> Em Tue, Dec 06, 2022 at 02:13:48PM -0300, Arnaldo Carvalho de Melo =
escreveu:
>> Em Tue, Dec 06, 2022 at 02:07:32PM -0300, Arnaldo Carvalho de Melo =
escreveu:
>>> Em Tue, Dec 06, 2022 at 02:01:43PM -0300, Arnaldo Carvalho de Melo =
escreveu:
>>>> Em Tue, Dec 06, 2022 at 01:41:41PM -0300, Arnaldo Carvalho de Melo =
escreveu:
>>>>> Now to look at the BUILD_BPF_SKEL=3D1 kaboom:
>>>>>=20
>>>>> [acme@quaco perf]$ alias m
>>>>> alias m=3D'rm -rf ~/libexec/perf-core/ ; make -k =
NO_LIBTRACEEVENT=3D1 BUILD_BPF_SKEL=3D1 O=3D/tmp/build/perf -C =
tools/perf install-bin && perf test python'
>>>>> [acme@quaco perf]$ m
>>>>> make: Entering directory '/home/acme/git/perf/tools/perf'
>>>>>  BUILD:   Doing 'make -j8' parallel build
>>>>>  <SNIP>
>>>>> /usr/bin/ld: /tmp/build/perf/perf-in.o: in function `add_work':
>>>>> /home/acme/git/perf/tools/perf/util/bpf_kwork.c:285: undefined =
reference to `perf_kwork_add_work'
>>>>> /usr/bin/ld: /tmp/build/perf/perf-in.o: in function =
`lock_contention_read':
>>>=20
>>> For that bpf_kwork.c see below. Now to see why the python binding is =
not
>>> building, I guess is unrelated and you have some other outstanding
>>> patch?
>>=20
>> Its related:
>>=20
>> [acme@quaco perf]$ perf test -v python
>> Couldn't bump rlimit(MEMLOCK), failures may take place when creating =
BPF maps, etc
>> 14: 'import perf' in python                                         :
>> --- start ---
>> test child forked, pid 1669872
>> python usage test: "echo "import sys ; =
sys.path.append('/tmp/build/perf/python'); import perf" | =
'/usr/bin/python3' "
>> Traceback (most recent call last):
>>  File "<stdin>", line 1, in <module>
>> ImportError: =
/tmp/build/perf/python/perf.cpython-310-x86_64-linux-gnu.so: undefined =
symbol: tep_unload_plugins
>> test child finished with -1
>> ---- end ----
>> 'import perf' in python: FAILED!
>> [acme@quaco perf]$
>>=20
>> Now checking why NO_LIBTRACEEVENT=3D1 fails with this...
>>=20
>> [acme@quaco perf]$ find tools/perf/ -name "*.c" | xargs grep =
tep_unload_plugins
>> tools/perf/util/trace-event.c:	=
tep_unload_plugins(t->plugin_list, t->pevent);
>> [acme@quaco perf]$
>>=20
>> [acme@quaco perf]$ grep trace-event =
tools/perf/util/python-ext-sources
>> util/trace-event.c
>> [acme@quaco perf]$
>>=20
>> Trying to fix...
>=20
> I'm missing some detail, this isn't working, util/trace-event.c is =
still
> being built and linked.

Hi,

Observed similar issue with =E2=80=9Cbuiltin-trace.c=E2=80=9D

In system without libtraceevent-devel, I could still see builtin-trace =
trying to get
compiled and hitting error. In my understanding, CONFIG_TRACE will be
disabled when libtraceevent is not present and hence builtin-trace =
should be disabled
which I am not seeing.

# rpm -qa|grep libtraceevent
libtraceevent-1.2.1-1.el8.ppc64le

# grep -i traceevent FEATURE-DUMP=20
feature-libtraceevent=3D0

Snippet from make logs:

builtin-trace.c:266:50: error: dereferencing pointer to incomplete type =
'struct tep_format_field'
  return __tp_field__init_uint(field, format_field->size, =
format_field->offset, needs_swap);
                                                  ^~
builtin-trace.c: In function 'evsel__syscall_arg_fmt':
builtin-trace.c:361:25: error: 'struct evsel' has no member named =
'tp_format'
   et->fmt =3D calloc(evsel->tp_format->format.nr_fields, sizeof(struct =
syscall_arg_fmt));


Thanks
Athira

>=20
> The python binding should be usable without tracepoints, in fact its
> first usage was just to have access to the perf metaevents, see=20
> tools/perf/python/twatch.py.
>=20
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index f0e4daeef8120853..5bd67d54d036f281 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -348,6 +348,10 @@ export PYTHON_EXTBUILD_LIB PYTHON_EXTBUILD_TMP
> python-clean :=3D $(call QUIET_CLEAN, python) $(RM) -r =
$(PYTHON_EXTBUILD) $(OUTPUT)python/perf*.so
>=20
> PYTHON_EXT_SRCS :=3D $(shell grep -v ^\# util/python-ext-sources)
> +ifneq ($(CONFIG_TRACEEVENT),y)
> +  PYTHON_EXT_SRCS :=3D $(call =
filter-out,$(PYTHON_EXT_SRCS),util/trace-event.c)
> +endif
> +
> PYTHON_EXT_DEPS :=3D util/python-ext-sources util/setup.py $(LIBAPI)
>=20
> SCRIPTS =3D $(patsubst %.sh,%,$(SCRIPT_SH))
> diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
> index 728fe2f51759eb0d..72088aec2857b316 100644
> --- a/tools/perf/util/python.c
> +++ b/tools/perf/util/python.c
> @@ -1330,6 +1330,9 @@ static struct {
> static PyObject *pyrf__tracepoint(struct pyrf_evsel *pevsel,
> 				  PyObject *args, PyObject *kwargs)
> {
> +#ifndef HAVE_LIBTRACEEVENT
> +	return NULL;
> +#else
> 	struct tep_event *tp_format;
> 	static char *kwlist[] =3D { "sys", "name", NULL };
> 	char *sys  =3D NULL;
> @@ -1344,6 +1347,7 @@ static PyObject *pyrf__tracepoint(struct =
pyrf_evsel *pevsel,
> 		return _PyLong_FromLong(-1);
>=20
> 	return _PyLong_FromLong(tp_format->id);
> +#endif // HAVE_LIBTRACEEVENT
> }
>=20
> static PyMethodDef perf__methods[] =3D {