Re: [PATCH v3 4/7] perf python: Add support for perf_counts_values to return counter data

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Thu, May 22, 2025 at 07:37:46PM -0300, Arnaldo Carvalho de Melo wrote:
> On Thu, May 22, 2025 at 07:36:31PM -0300, Arnaldo Carvalho de Melo wrote:
> > On Thu, May 22, 2025 at 03:32:44PM -0700, Ian Rogers wrote:
> > > On Thu, May 22, 2025 at 3:20 PM Arnaldo Carvalho de Melo
> > > <acme@kernel.org> wrote:
> > > >
> > > > On Mon, May 19, 2025 at 12:51:41PM -0700, Ian Rogers wrote:
> > > > > From: Gautam Menghani <gautam@linux.ibm.com>
> > > > >
> > > > > Add support for perf_counts_values struct to enable the python
> > > > > bindings to read and return the counter data.
> > > > >
> > > > > Signed-off-by: Gautam Menghani <gautam@linux.ibm.com>
> > > > > ---
> > > > >  tools/perf/util/python.c | 92 +++++++++++++++++++++++++++++++++++++++-
> > > > >  1 file changed, 91 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
> > > > > index ead3afd2d996..1cbddfe77c7c 100644
> > > > > --- a/tools/perf/util/python.c
> > > > > +++ b/tools/perf/util/python.c
> > > > > @@ -626,6 +626,92 @@ static int pyrf_thread_map__setup_types(void)
> > > > >       return PyType_Ready(&pyrf_thread_map__type);
> > > > >  }
> > > > >
> > > > > +struct pyrf_counts_values {
> > > > > +     PyObject_HEAD
> > > > > +
> > > > > +     struct perf_counts_values values;
> > > > > +};
> > > > > +
> > > > > +static const char pyrf_counts_values__doc[] = PyDoc_STR("perf counts values object.");
> > > > > +
> > > > > +static void pyrf_counts_values__delete(struct pyrf_counts_values *pcounts_values)
> > > > > +{
> > > > > +     Py_TYPE(pcounts_values)->tp_free((PyObject *)pcounts_values);
> > > > > +}
> > > > > +
> > > > > +#define counts_values_member_def(member, ptype, help) \
> > > > > +     { #member, ptype, \
> > > > > +       offsetof(struct pyrf_counts_values, values.member), \
> > > > > +       0, help }
> > > > > +
> > > > > +static PyMemberDef pyrf_counts_values_members[] = {
> > > > > +     counts_values_member_def(val, Py_T_ULONG, "Value of event"),
> > > > > +     counts_values_member_def(ena, Py_T_ULONG, "Time for which enabled"),
> > > > > +     counts_values_member_def(run, Py_T_ULONG, "Time for which running"),
> > > > > +     counts_values_member_def(id, Py_T_ULONG, "Unique ID for an event"),
> > > > > +     counts_values_member_def(lost, Py_T_ULONG, "Num of lost samples"),
> > > > > +     {NULL}
> > > > > +};
> > > >
> > > > So the above is failing on a aarch64 debian (rpi5):
> > > >
> > > > acme@raspberrypi:~/git/perf-tools-next $ dpkg -S /usr/include/python3.11/structmember.h
> > > > libpython3.11-dev:arm64: /usr/include/python3.11/structmember.h
> > > > acme@raspberrypi:~/git/perf-tools-next $
> > > >
> > > > Where it only has:
> > > >
> > > > acme@raspberrypi:~/git/perf-tools-next $ grep -r Py_T_ULONG /usr/include/
> > > > acme@raspberrypi:~/git/perf-tools-next $ grep -rw Py_T_ULONG /usr/include/
> > > > acme@raspberrypi:~/git/perf-tools-next $ grep -rw T_ULONG /usr/include/
> > > > /usr/include/python3.11/structmember.h:#define T_ULONG     12
> > > > acme@raspberrypi:~/git/perf-tools-next $
> > > >
> > > > while on fedora 42 x86_64:
> > > >
> > > > ⬢ [acme@toolbx perf-tools-next]$ grep -rw Py_T_ULONG /usr/include/
> > > > /usr/include/python3.13/descrobject.h:#define Py_T_ULONG     12
> > > > /usr/include/python3.13/structmember.h:#define T_ULONG     Py_T_ULONG
> > > > ⬢ [acme@toolbx perf-tools-next]$
> > > >
> > > > So I'm making it use the T_ULONG and others as all the other PyMemberDef
> > > > arrays in tools/perf/util/python.c, ok?
> > > 
> > > The fix makes sense to me. Checking the documentation it seems
> > > Py_T_ULONG is preferred:
> > > https://docs.python.org/3/c-api/structures.html#member-types
> > > perhaps we can add:
> > > ```
> > > #ifndef Py_T_ULONG
> > > #define Py_T_ULONG T_ULONG
> > > #endif
> > > ```
> > > so that we use the approach matching the documentation while fixing
> > > the RaspberryPi issue.
> > 
> > That can be done as a followup, as there are lots of preexisting usage
> > for struct method definitions.
> 
> And there is one other issue:
> 
>   LINK    /tmp/build/perf/perf
>   GEN     /tmp/build/perf/python/perf.cpython-36m-x86_64-linux-gnu.so
> /git/perf-6.15.0-rc7/tools/perf/util/python.c:653:7: error: missing field 'type' initializer [-Werror,-Wmissing-field-initializers]
>   653 |         {NULL}
>       |              ^
> /git/perf-6.15.0-rc7/tools/perf/util/python.c:695:7: error: missing field 'get' initializer [-Werror,-Wmissing-field-initializers]
>   695 |         {NULL}
>       |              ^
> 2 errors generated.
> error: command 'clang' failed with exit status 1
> cp: cannot stat '/tmp/build/perf/python_ext_build/lib/perf*.so': No such file or directory
> 
> 
> I'll look at this after dinner.

Doing the same thing as for all the other PyMemberDef arrays makes it
pass that hurdle:

⬢ [acme@toolbx perf-tools-next]$ git diff
diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index cb5a76674a5f1078..60ff12e90b91f97c 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -650,7 +650,7 @@ static PyMemberDef pyrf_counts_values_members[] = {
        counts_values_member_def(run, T_ULONG, "Time for which running"),
        counts_values_member_def(id, T_ULONG, "Unique ID for an event"),
        counts_values_member_def(lost, T_ULONG, "Num of lost samples"),
-       {NULL}
+       { .name = NULL, },
 };

 static PyObject *pyrf_counts_values_get_values(struct pyrf_counts_values *self, void *closure)

Then there is:

  GEN     /tmp/build/perf/python/perf.cpython-36m-x86_64-linux-gnu.so
/git/perf-6.15.0-rc7/tools/perf/util/python.c:695:8: error: missing field 'get' initializer [-Werror,-Wmissing-field-initializers]
  695 |         {NULL,}
      |               ^
1 error generated.
error: command 'clang' failed with exit status 1

I tried with the ending NULL, but it wasn't enough, so I'm going with:

⬢ [acme@toolbx perf-tools-next]$ git diff
diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 5fa113daf4488120..21e2da1ec0c6342c 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -692,7 +692,7 @@ static int pyrf_counts_values_set_values(struct pyrf_counts_values *self, PyObje
 static PyGetSetDef pyrf_counts_values_getset[] = {
        {"values", (getter)pyrf_counts_values_get_values, (setter)pyrf_counts_values_set_values,
                "Name field", NULL},
-       {NULL,}
+       { .name = NULL, },
 };
 
 static PyTypeObject pyrf_counts_values__type = {
⬢ [acme@toolbx perf-tools-next]$ 

- Arnaldo