simpleperf: fix report_html.py.

report_html.py removes threads having too small percentage
of samples. But it doesn't remove processes having no threads,
which makes showing flamegraph broken.

Bug: none
Test: run test.py TestReportHtml.test_no_empty_process.
Change-Id: I3d568c98f0426a8ebbc9760dbc3c2bd25eda4c67

3 files changed, 20 insertions, 0 deletions

diff --git a/simpleperf/scripts/report_html.py b/simpleperf/scripts/report_html.py
index d7fe0ecf..f2292720 100755
--- a/simpleperf/scripts/report_html.py
+++ b/simpleperf/scripts/report_html.py
@@ -642,6 +642,7 @@ class RecordData(object):
         hit_func_ids = set()
         for event in self.events.values():
             min_limit = event.event_count * min_func_percent * 0.01
+            to_del_processes = []
             for process in event.processes.values():
                 to_del_threads = []
                 for thread in process.threads.values():
@@ -651,6 +652,10 @@ class RecordData(object):
                         thread.limit_percents(min_limit, min_callchain_percent, hit_func_ids)
                 for thread in to_del_threads:
                     del process.threads[thread]
+                if not process.threads:
+                    to_del_processes.append(process.pid)
+            for process in to_del_processes:
+                del event.processes[process]
         self.functions.trim_functions(hit_func_ids)
 
     def _get_event(self, event_name):
diff --git a/simpleperf/scripts/script_testdata/two_process_perf.data b/simpleperf/scripts/script_testdata/two_process_perf.data
new file mode 100644
index 00000000..c61d5916
--- /dev/null
+++ b/simpleperf/scripts/script_testdata/two_process_perf.data
diff --git a/simpleperf/scripts/test.py b/simpleperf/scripts/test.py
index 1b01c5f9..24a04356 100755
--- a/simpleperf/scripts/test.py
+++ b/simpleperf/scripts/test.py
@@ -1285,6 +1285,21 @@ class TestReportHtml(TestBase):
                 hit_count += 1
         self.assertEqual(hit_count, len(event_count_for_thread_name))
 
+    def test_no_empty_process(self):
+        """ Test not showing a process having no threads. """
+        perf_data = os.path.join('testdata', 'two_process_perf.data')
+        self.run_cmd(['report_html.py', '-i', perf_data])
+        record_data = self._load_record_data_in_html('report.html')
+        processes = record_data['sampleInfo'][0]['processes']
+        self.assertEqual(len(processes), 2)
+
+        # One process is removed because all its threads are removed for not
+        # reaching the min_func_percent limit.
+        self.run_cmd(['report_html.py', '-i', perf_data, '--min_func_percent', '20'])
+        record_data = self._load_record_data_in_html('report.html')
+        processes = record_data['sampleInfo'][0]['processes']
+        self.assertEqual(len(processes), 1)
+
     def _load_record_data_in_html(self, html_file):
         with open(html_file, 'r') as fh:
             data = fh.read()