[PATCH v9 12/16] perf python: Add parse_metrics function

[Ian Rogers <irogers@google.com>]

Add parse_metrics function that takes a string of metrics and/or
metric groups and returns the evlist containing the events and
metrics.

For example:
```
>>> import perf
>>> perf.parse_metrics("TopdownL1")
evlist([cpu/TOPDOWN.SLOTS/,cpu/topdown-retiring/,cpu/topdown-fe-bound/,
cpu/topdown-be-bound/,cpu/topdown-bad-spec/,cpu/INT_MISC.CLEARS_COUNT/,
cpu/INT_MISC.UOP_DROPPING/])
```

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/python.c | 41 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index d49b4401ab7e..3a58080bab24 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -1881,6 +1881,40 @@ static PyObject *pyrf__parse_events(PyObject *self, PyObject *args)
 	return result;
 }
 
+static PyObject *pyrf__parse_metrics(PyObject *self, PyObject *args)
+{
+	const char *input;
+	struct evlist evlist = {};
+	PyObject *result;
+	PyObject *pcpus = NULL, *pthreads = NULL;
+	struct perf_cpu_map *cpus;
+	struct perf_thread_map *threads;
+	int ret;
+
+	if (!PyArg_ParseTuple(args, "s|OO", &input, &pcpus, &pthreads))
+		return NULL;
+
+	threads = pthreads ? ((struct pyrf_thread_map *)pthreads)->threads : NULL;
+	cpus = pcpus ? ((struct pyrf_cpu_map *)pcpus)->cpus : NULL;
+
+	evlist__init(&evlist, cpus, threads);
+	ret = metricgroup__parse_groups(&evlist, /*pmu=*/"all", input,
+					/*metric_no_group=*/ false,
+					/*metric_no_merge=*/ false,
+					/*metric_no_threshold=*/ true,
+					/*user_requested_cpu_list=*/ NULL,
+					/*system_wide=*/true,
+					/*hardware_aware_grouping=*/ false);
+	if (ret) {
+		errno = -ret;
+		PyErr_SetFromErrno(PyExc_OSError);
+		return NULL;
+	}
+	result = pyrf_evlist__from_evlist(&evlist);
+	evlist__exit(&evlist);
+	return result;
+}
+
 static PyMethodDef perf__methods[] = {
 	{
 		.ml_name  = "tracepoint",
@@ -1894,6 +1928,13 @@ static PyMethodDef perf__methods[] = {
 		.ml_flags = METH_VARARGS,
 		.ml_doc	  = PyDoc_STR("Parse a string of events and return an evlist.")
 	},
+	{
+		.ml_name  = "parse_metrics",
+		.ml_meth  = (PyCFunction) pyrf__parse_metrics,
+		.ml_flags = METH_VARARGS,
+		.ml_doc	  = PyDoc_STR(
+			"Parse a string of metics or metric groups and return an evlist.")
+	},
 	{
 		.ml_name  = "pmus",
 		.ml_meth  = (PyCFunction) pyrf__pmus,
-- 
2.50.1.552.g942d659e1b-goog