Tracing on startup on flutter/engine@6d0c4e5 with and w/o --optimization_counter_threshold=-1

gistfile1.txt

On 6d0c4e5.

diff --git a/sky/engine/core/script/dart_init.cc b/sky/engine/core/script/dart_init.cc
index e7a9d45..9d71485 100644
--- a/sky/engine/core/script/dart_init.cc
+++ b/sky/engine/core/script/dart_init.cc
@@ -64,6 +64,7 @@ void CreateEmptyRootLibraryIfNeeded() {
 
 static const char* kDartArgs[] = {
     "--enable_mirrors=false",
+    "--optimization_counter_threshold=-1",
     // Dart assumes ARM devices are insufficiently powerful and sets the
     // default profile period to 100Hz. This number is suitable for older
     // Raspberry Pi devices but quite low for current smartphones.

5 runs using examples/stocks:
Installing SkyShell.apk on device.
Trace file saved to /tmp/trace_1.json
  1 1528.636
Trace file saved to /tmp/trace_2.json
  2 1455.591
Trace file saved to /tmp/trace_3.json
  3 1502.779
Trace file saved to /tmp/trace_4.json
  4 1464.564
Trace file saved to /tmp/trace_5.json
  5 1495.28
mean: 1489.37
median: 1495.28


Without:

./dev/profile_startup.dart examples/stocks                                                                                                                    [/src/flutter]
Profiling startup using flutter start --trace-startup.
Measuring from first trace event to completion of first frame upload.
aka NativeViewGLSurfaceEGL:RealSwapBuffers.

NOTE: If device is not on/unlocked tracing may fail.

5 runs using examples/stocks:
Installing SkyShell.apk on device.
Trace file saved to /tmp/trace_1.json
  1 1358.532
Trace file saved to /tmp/trace_2.json
  2 1498.642
Trace file saved to /tmp/trace_3.json
  3 1505.564
Trace file saved to /tmp/trace_4.json
  4 1516.476
Trace file saved to /tmp/trace_5.json
  5 1552.79
mean: 1486.4008
median: 1505.564
eseidel@eseidel2 /src/flutter %