Telemetry: Remove 'overhead' time from thread times measurement.

tools/perf/metrics/timeline.py

Index: tools/perf/metrics/timeline.py
diff --git a/tools/perf/metrics/timeline.py b/tools/perf/metrics/timeline.py
index 01cd130c46c9c914b2e0082a60575db8bdb6054c..786234628657d8e5ccbc57aa014f948772af83ea 100644
--- a/tools/perf/metrics/timeline.py
+++ b/tools/perf/metrics/timeline.py
@@ -140,8 +140,8 @@ TimelineThreadCategories =  {
   "Chrome_InProcGpuThread": "GPU",
   "CrGpuMain"             : "GPU",
   "AsyncTransferThread"   : "GPU_transfer",
-  "CrBrowserMain"         : "browser_main",
-  "Browser Compositor"    : "browser_compositor",
+  "CrBrowserMain"         : "browser",
+  "Browser Compositor"    : "browser",
   "CrRendererMain"        : "renderer_main",
   "Compositor"            : "renderer_compositor",
   "IOThread"              : "IO",
@@ -155,20 +155,34 @@ MatchBySubString = ["IOThread", "CompositorRasterWorker"]
 
 AllThreads = TimelineThreadCategories.values()
 NoThreads = []
-FastPathThreads = ["GPU",
-                   "browser_main",
-                   "browser_compositor",
-                   "renderer_compositor",
-                   "IO"]
-MainThread = ["renderer_main"]
+
+FastPathThreads = ["GPU", "renderer_compositor", "browser", "IO"]
 FastPathResults = AllThreads
 FastPathDetails = NoThreads
 SilkResults = ["renderer_main", "total_all"]
-SilkDetails = MainThread
+SilkDetails = ["renderer_main"]
 
 # TODO(epenner): Thread names above are likely fairly stable but trace names
-# could change. We should formalize this trace to keep this robust.
-CompositorFrameTraceName = "::SwapBuffers"
+# could change. We should formalize these traces to keep this robust.
+OverheadTraceCategory = "trace_event_overhead"

[nduca, 2014/02/05 00:34:11]

global vars sould be prefixed with _ when not intended for use outside the
module

+OverheadTraceName = "overhead"
+FrameTraceName = "::SwapBuffers"
+FrameTraceThread = "renderer_compositor"
+
+def ClockOverhead(event):

[nduca, 2014/02/05 00:34:11]

GetClockOverheadFromEvent

+  if (event.category == OverheadTraceCategory and
+      event.name == OverheadTraceName):
+    return event.duration
+  else:
+    return 0
+
+def CpuOverhead(event):

[nduca, 2014/02/05 00:34:11]

GetCpuOverheadFromEvent or someting like that

+  if (event.category == OverheadTraceCategory and
+      event.name == OverheadTraceName and
+      event.thread_duration):
+    return event.thread_duration
+  else:
+    return 0
 
 def ThreadCategoryName(thread_name):
   thread_category = "other"
@@ -198,11 +212,14 @@ class ResultsForThread(object):
 
   @property
   def clock_time(self):
-    return sum([x.duration for x in self.toplevel_slices])
+    clock_duration = sum([x.duration for x in self.toplevel_slices])
+    clock_overhead = sum([ClockOverhead(x) for x in self.all_slices])
+    return clock_duration - clock_overhead
 
   @property
   def cpu_time(self):
-    res = 0
+    cpu_duration = 0
+    cpu_overhead = sum([CpuOverhead(x) for x in self.all_slices])
     for x in self.toplevel_slices:
       # Only report thread-duration if we have it for all events.
       #
@@ -213,8 +230,8 @@ class ResultsForThread(object):
         else:
           return 0
       else:
-        res += x.thread_duration
-    return res
+        cpu_duration += x.thread_duration
+    return cpu_duration - cpu_overhead
 
   def ActionSlices(self, slices):
     slices_in_actions = []
@@ -293,9 +310,9 @@ class ThreadTimesTimelineMetric(TimelineMetric):
       if ThreadCategoryName(thread.name) in FastPathThreads:
         thread_category_results['total_fast_path'].AppendThreadSlices(thread)
 
-    # Calculate the number of frames from the CC thread.
-    cc_slices = thread_category_results['renderer_compositor'].all_slices
-    num_frames = self.CountSlices(cc_slices, CompositorFrameTraceName)
+    # Calculate the number of frames.
+    frame_slices = thread_category_results[FrameTraceThread].all_slices
+    num_frames = self.CountSlices(frame_slices, FrameTraceName)
 
     # Report the desired results and details.
     for thread_results in thread_category_results.values():