Add a dual clock profiler tracing mode.

Dalvik previously supported using either the thread-cpu clock
or the real time clock as the timebase for profiler traces.
This change adds a dual clock mode where both thread-cpu time
and real time timestamps are collected.

Using dual clock mode significantly improves TraceView ability
to accurately reconstruct the global timeline of events,
particularly on SMP systems.

For now, thread-cpu mode remains the default.

Dual clock mode can be enabled by running the following command
and restarting the system server.
   adb shell setprop dalvik.vm.extra-opts -Xprofile:dualclock

Change-Id: I8c0d91a99aa6829dadea328e54dc1225d9827391

1 files changed, 10 insertions, 2 deletions

diff --git a/vm/Globals.h b/vm/Globals.h
index bf92781ef..fcb6b29b8 100644
--- a/vm/Globals.h
+++ b/vm/Globals.h
@@ -67,6 +67,15 @@ enum RegisterMapMode {
 };
 
 /*
+ * Profiler clock source.
+ */
+enum ProfilerClockSource {
+    kProfilerClockSourceThreadCpu,
+    kProfilerClockSourceWall,
+    kProfilerClockSourceDual,
+};
+
+/*
  * All fields are initialized to zero.
  *
  * Storage allocated here must be freed by a subsystem shutdown function.
@@ -96,8 +105,7 @@ struct DvmGlobals {
     int         jdwpPort;
     bool        jdwpSuspend;
 
-    /* use wall clock as method profiler clock source? */
-    bool        profilerWallClock;
+    ProfilerClockSource profilerClockSource;
 
     /*
      * Lock profiling threshold value in milliseconds.  Acquires that