[PATCH v4 06/15] perf python: Add basic PMU abstraction and pmus sequence

[Ian Rogers <irogers@google.com>]

Add an ability to iterate over PMUs and a basic PMU type then can just
show the PMU's name.

An example usage:
```
$ python
Python 3.12.9 (main, Feb  5 2025, 01:31:18) [GCC 14.2.0] on linux
>>> import perf
>>> list(perf.pmus())
[pmu(cpu), pmu(breakpoint), pmu(cstate_core), pmu(cstate_pkg),
pmu(hwmon_acpitz), pmu(hwmon_ac), pmu(hwmon_bat0),
pmu(hwmon_coretemp), pmu(hwmon_iwlwifi_1), pmu(hwmon_nvme),
pmu(hwmon_thinkpad), pmu(hwmon_ucsi_source_psy_usbc000_0),
pmu(hwmon_ucsi_source_psy_usbc000_0), pmu(i915), pmu(intel_bts),
pmu(intel_pt), pmu(kprobe), pmu(msr), pmu(power), pmu(software),
pmu(tool), pmu(tracepoint), pmu(uncore_arb), pmu(uncore_cbox_0),
pmu(uncore_cbox_1), pmu(uncore_cbox_2), pmu(uncore_cbox_3),
pmu(uncore_cbox_4), pmu(uncore_cbox_5), pmu(uncore_cbox_6),
pmu(uncore_cbox_7), pmu(uncore_clock), pmu(uncore_imc_free_running_0),
pmu(uncore_imc_free_running_1), pmu(uprobe)]
```

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/python.c | 140 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 140 insertions(+)

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 201fe04fb6dd..33b23d56dfb1 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -627,6 +627,138 @@ static int pyrf_thread_map__setup_types(void)
 	return PyType_Ready(&pyrf_thread_map__type);
 }
 
+/**
+ * A python wrapper for perf_pmus that are globally owned by the pmus.c code.
+ */
+struct pyrf_pmu {
+	PyObject_HEAD
+
+	struct perf_pmu *pmu;
+};
+
+static void pyrf_pmu__delete(struct pyrf_pmu *ppmu)
+{
+	Py_TYPE(ppmu)->tp_free((PyObject *)ppmu);
+}
+
+static PyObject *pyrf_pmu__name(PyObject *self)
+{
+	struct pyrf_pmu *ppmu = (void *)self;
+
+	return PyUnicode_FromString(ppmu->pmu->name);
+}
+
+static PyObject *pyrf_pmu__repr(PyObject *self)
+{
+	struct pyrf_pmu *ppmu = (void *)self;
+
+	return PyUnicode_FromFormat("pmu(%s)", ppmu->pmu->name);
+}
+
+static const char pyrf_pmu__doc[] = PyDoc_STR("perf Performance Monitoring Unit (PMU) object.");
+
+static PyMethodDef pyrf_pmu__methods[] = {
+	{
+		.ml_name  = "name",
+		.ml_meth  = (PyCFunction)pyrf_pmu__name,
+		.ml_flags = METH_NOARGS,
+		.ml_doc	  = PyDoc_STR("Name of the PMU including suffixes.")
+	},
+	{ .ml_name = NULL, }
+};
+
+/** The python type for a perf.pmu. */
+static PyTypeObject pyrf_pmu__type = {
+	PyVarObject_HEAD_INIT(NULL, 0)
+	.tp_name	= "perf.pmu",
+	.tp_basicsize	= sizeof(struct pyrf_pmu),
+	.tp_dealloc	= (destructor)pyrf_pmu__delete,
+	.tp_flags	= Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE,
+	.tp_doc		= pyrf_pmu__doc,
+	.tp_methods	= pyrf_pmu__methods,
+	.tp_str         = pyrf_pmu__name,
+	.tp_repr        = pyrf_pmu__repr,
+};
+
+static int pyrf_pmu__setup_types(void)
+{
+	pyrf_pmu__type.tp_new = PyType_GenericNew;
+	return PyType_Ready(&pyrf_pmu__type);
+}
+
+
+/** A python iterator for pmus that has no equivalent in the C code. */
+struct pyrf_pmu_iterator {
+	PyObject_HEAD
+	struct perf_pmu *pmu;
+};
+
+static void pyrf_pmu_iterator__dealloc(struct pyrf_pmu_iterator *self)
+{
+	Py_TYPE(self)->tp_free((PyObject *) self);
+}
+
+static PyObject *pyrf_pmu_iterator__new(PyTypeObject *type, PyObject *args __maybe_unused,
+					PyObject *kwds __maybe_unused)
+{
+	struct pyrf_pmu_iterator *itr = (void *)type->tp_alloc(type, 0);
+
+	if (itr != NULL)
+		itr->pmu = perf_pmus__scan(/*pmu=*/NULL);
+
+	return (PyObject *) itr;
+}
+
+static PyObject *pyrf_pmu_iterator__iter(PyObject *self)
+{
+	Py_INCREF(self);
+	return self;
+}
+
+static PyObject *pyrf_pmu_iterator__iternext(PyObject *self)
+{
+	struct pyrf_pmu_iterator *itr = (void *)self;
+	struct pyrf_pmu *ppmu;
+
+	if (itr->pmu == NULL) {
+		PyErr_SetNone(PyExc_StopIteration);
+		return NULL;
+	}
+	// Create object to return.
+	ppmu = PyObject_New(struct pyrf_pmu, &pyrf_pmu__type);
+	if (ppmu) {
+		ppmu->pmu = itr->pmu;
+		// Advance iterator.
+		itr->pmu = perf_pmus__scan(itr->pmu);
+	}
+	return (PyObject *)ppmu;
+}
+
+/** The python type for the PMU iterator. */
+static PyTypeObject pyrf_pmu_iterator__type = {
+	PyVarObject_HEAD_INIT(NULL, 0)
+	.tp_name = "pmus.iterator",
+	.tp_doc = "Iterator for the pmus string sequence.",
+	.tp_basicsize = sizeof(struct pyrf_pmu_iterator),
+	.tp_itemsize = 0,
+	.tp_flags = Py_TPFLAGS_DEFAULT,
+	.tp_new = pyrf_pmu_iterator__new,
+	.tp_dealloc = (destructor) pyrf_pmu_iterator__dealloc,
+	.tp_iter = pyrf_pmu_iterator__iter,
+	.tp_iternext = pyrf_pmu_iterator__iternext,
+};
+
+static int pyrf_pmu_iterator__setup_types(void)
+{
+	return PyType_Ready(&pyrf_pmu_iterator__type);
+}
+
+static PyObject *pyrf__pmus(PyObject *self, PyObject *args)
+{
+	// Calling the class creates an instance of the iterator.
+	return PyObject_CallObject((PyObject *) &pyrf_pmu_iterator__type, /*args=*/NULL);
+}
+
 struct pyrf_counts_values {
 	PyObject_HEAD
 
@@ -1613,6 +1745,12 @@ static PyMethodDef perf__methods[] = {
 		.ml_flags = METH_VARARGS,
 		.ml_doc	  = PyDoc_STR("Parse a string of events and return an evlist.")
 	},
+	{
+		.ml_name  = "pmus",
+		.ml_meth  = (PyCFunction) pyrf__pmus,
+		.ml_flags = METH_NOARGS,
+		.ml_doc	  = PyDoc_STR("Returns a sequence of pmus.")
+	},
 	{ .ml_name = NULL, }
 };
 
@@ -1640,6 +1778,8 @@ PyMODINIT_FUNC PyInit_perf(void)
 	    pyrf_evsel__setup_types() < 0 ||
 	    pyrf_thread_map__setup_types() < 0 ||
 	    pyrf_cpu_map__setup_types() < 0 ||
+	    pyrf_pmu_iterator__setup_types() < 0 ||
+	    pyrf_pmu__setup_types() < 0 ||
 	    pyrf_counts_values__setup_types() < 0)
 		return module;
 
-- 
2.50.0.727.gbf7dc18ff4-goog