Index: tools/telemetry/telemetry/web_perf/metrics/mainthread_jank_stats.py |
diff --git a/tools/telemetry/telemetry/web_perf/metrics/mainthread_jank_stats.py b/tools/telemetry/telemetry/web_perf/metrics/mainthread_jank_stats.py |
new file mode 100644 |
index 0000000000000000000000000000000000000000..66a86a7052fe95d1d010ce47ac4a61cd8c5bc9b0 |
--- /dev/null |
+++ b/tools/telemetry/telemetry/web_perf/metrics/mainthread_jank_stats.py |
@@ -0,0 +1,91 @@ |
+# Copyright 2014 The Chromium Authors. All rights reserved. |
+# Use of this source code is governed by a BSD-style license that can be |
+# found in the LICENSE file. |
+ |
+ |
+# A top level slice of a main thread can cause the webapp to behave |
+# unresponsively if its thread duration is greater than or equals to |
+# USER_PERCEIVABLE_DELAY_THRESHOLD_MS. Human eyes can perceive delay at low as |
+# 100ms, but since we use thread time instead of wall-time, we reduce the |
+# threshold further to 50ms to make room for other OS's activities. |
+USER_PERCEIVABLE_DELAY_THRESHOLD_MS = 50 |
+ |
+ |
+class _MainthreadJankStat(object): |
+ """A small wrapper class for storing mainthread jank stats computed for |
+ single record. |
+ """ |
+ |
+ def __init__(self): |
+ self.sum_big_top_slices_thread_time = 0 |
+ self.biggest_top_slice_thread_time = 0 |
+ |
+ |
+def _ComputeMainthreadJankStatsForRecord(renderer_thread, record): |
+ """Computes the mainthread jank stat on a record range. |
+ |
+ Returns: |
+ An instance of _MainthreadJankStat, which has: |
+ |
+ sum_big_top_slices_thread_time is the total thread duration of all top |
+ slices whose thread time ranges overlapped with (thread_start, thread_end) |
+ and the overlapped thread duration is greater than or equal |
+ USER_PERCEIVABLE_DELAY_THRESHOLD_MS. |
+ |
+ biggest_top_slice_thread_time is the biggest thread duration of all |
+ top slices whose thread time ranges overlapped with |
+ (thread_start, thread_end). |
+ |
+ Note: thread duration of each slices is computed using overlapped range |
+ with (thread_start, thread_end). |
+ """ |
+ stat = _MainthreadJankStat() |
+ for s in renderer_thread.toplevel_slices: |
+ jank_thread_duration = record.GetOverlappedThreadTimeForSlice(s) |
+ stat.biggest_top_slice_thread_time = max( |
+ stat.biggest_top_slice_thread_time, jank_thread_duration) |
+ if jank_thread_duration >= USER_PERCEIVABLE_DELAY_THRESHOLD_MS: |
+ stat.sum_big_top_slices_thread_time += jank_thread_duration |
+ return stat |
+ |
+ |
+class MainthreadJankStats(object): |
+ """ |
+ Utility class for extracting main thread jank statistics from the timeline |
+ (or other loggin facilities), and providing them in a common format to |
+ classes that compute benchmark metrics from this data. |
+ |
+ total_big_jank_thread_time is the total thread duration of all top |
+ slices whose thread time ranges overlapped with any thread time ranges of |
+ the records and the overlapped thread duration is greater than or equal |
+ USER_PERCEIVABLE_DELAY_THRESHOLD_MS. |
+ |
+ biggest_jank_thread_time is the biggest thread duration of all |
+ top slices whose thread time ranges overlapped with any of records' thread |
+ time ranges. |
+ """ |
+ |
+ def __init__(self, renderer_thread, interaction_records): |
+ self._renderer_thread = renderer_thread |
+ self._interaction_records = interaction_records |
+ self._total_big_jank_thread_time = 0 |
+ self._biggest_jank_thread_time = 0 |
+ self._ComputeMainthreadJankStats() |
+ |
+ @property |
+ def total_big_jank_thread_time(self): |
+ return self._total_big_jank_thread_time |
+ |
+ @property |
+ def biggest_jank_thread_time(self): |
+ return self._biggest_jank_thread_time |
+ |
+ def _ComputeMainthreadJankStats(self): |
+ for record in self._interaction_records: |
+ record_jank_stat = _ComputeMainthreadJankStatsForRecord( |
+ self._renderer_thread, record) |
+ self._total_big_jank_thread_time += ( |
+ record_jank_stat.sum_big_top_slices_thread_time) |
+ self._biggest_jank_thread_time = ( |
+ max(self._biggest_jank_thread_time, |
+ record_jank_stat.biggest_top_slice_thread_time)) |