perf python: Add evsel read method

Add the evsel read method to enable python to read counter data for the
given evsel.

Signed-off-by: Gautam Menghani <gautam@linux.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/linux-perf-users/20250512055748.479786-1-gautam@linux.ibm.com/
Link: https://lore.kernel.org/r/20250519195148.1708988-6-irogers@google.com
[ make the API take a CPU and thread then compute from these the appropriate indices. ]
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 21e2da1ec0c6342cd35b272dcdaf3fbc0b53df40..3155efb0ed436fa4aa020798d721a8fb5206d9de 100644 (file)
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -888,6 +888,37 @@ static PyObject *pyrf_evsel__threads(struct pyrf_evsel *pevsel)
        return (PyObject *)pthread_map;
 }
 
+static PyObject *pyrf_evsel__read(struct pyrf_evsel *pevsel,
+                                 PyObject *args, PyObject *kwargs)
+{
+       struct evsel *evsel = &pevsel->evsel;
+       int cpu = 0, cpu_idx, thread = 0, thread_idx;
+       struct perf_counts_values counts;
+       struct pyrf_counts_values *count_values = PyObject_New(struct pyrf_counts_values,
+                                                              &pyrf_counts_values__type);
+
+       if (!count_values)
+               return NULL;
+
+       if (!PyArg_ParseTuple(args, "ii", &cpu, &thread))
+               return NULL;
+
+       cpu_idx = perf_cpu_map__idx(evsel->core.cpus, (struct perf_cpu){.cpu = cpu});
+       if (cpu_idx < 0) {
+               PyErr_Format(PyExc_TypeError, "CPU %d is not part of evsel's CPUs", cpu);
+               return NULL;
+       }
+       thread_idx = perf_thread_map__idx(evsel->core.threads, thread);
+       if (cpu_idx < 0) {
+               PyErr_Format(PyExc_TypeError, "Thread %d is not part of evsel's threads",
+                            thread);
+               return NULL;
+       }
+       perf_evsel__read(&(evsel->core), cpu_idx, thread_idx, &counts);
+       count_values->values = counts;
+       return (PyObject *)count_values;
+}
+
 static PyObject *pyrf_evsel__str(PyObject *self)
 {
        struct pyrf_evsel *pevsel = (void *)self;
@@ -918,6 +949,12 @@ static PyMethodDef pyrf_evsel__methods[] = {
                .ml_flags = METH_NOARGS,
                .ml_doc   = PyDoc_STR("threads the event is to be used with.")
        },
+       {
+               .ml_name  = "read",
+               .ml_meth  = (PyCFunction)pyrf_evsel__read,
+               .ml_flags = METH_VARARGS | METH_KEYWORDS,
+               .ml_doc   = PyDoc_STR("read counters")
+       },
        { .ml_name = NULL, }
 };