5 files changed, 23 insertions, 5 deletions

diff --git a/cmds/app_process/app_main.cpp b/cmds/app_process/app_main.cpp
index c5af992..449a4ab 100644
--- a/cmds/app_process/app_main.cpp
+++ b/cmds/app_process/app_main.cpp
@@ -90,9 +90,6 @@ public:
 
     virtual void onZygoteInit()
     {
-        // Re-enable tracing now that we're no longer in Zygote.
-        atrace_set_tracing_enabled(true);
-
         sp<ProcessState> proc = ProcessState::self();
         ALOGV("App process: starting thread pool.\n");
         proc->startThreadPool();
diff --git a/core/java/android/app/ActivityThread.java b/core/java/android/app/ActivityThread.java
index e21c04a..828dc0a 100644
--- a/core/java/android/app/ActivityThread.java
+++ b/core/java/android/app/ActivityThread.java
@@ -5375,6 +5375,7 @@ public final class ActivityThread {
     }
 
     public static void main(String[] args) {
+        Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "ActivityThreadMain");
         SamplingProfilerIntegration.start();
 
         // CloseGuard defaults to true and can be quite spammy.  We
@@ -5409,6 +5410,8 @@ public final class ActivityThread {
                     LogPrinter(Log.DEBUG, "ActivityThread"));
         }
 
+        // End of event ActivityThreadMain.
+        Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
         Looper.loop();
 
         throw new RuntimeException("Main thread loop unexpectedly exited");
diff --git a/core/java/com/android/internal/os/RuntimeInit.java b/core/java/com/android/internal/os/RuntimeInit.java
index 2539a35..f81658e 100644
--- a/core/java/com/android/internal/os/RuntimeInit.java
+++ b/core/java/com/android/internal/os/RuntimeInit.java
@@ -24,6 +24,7 @@ import android.os.Debug;
 import android.os.IBinder;
 import android.os.Process;
 import android.os.SystemProperties;
+import android.os.Trace;
 import android.util.Log;
 import android.util.Slog;
 import com.android.internal.logging.AndroidConfig;
@@ -269,11 +270,11 @@ public class RuntimeInit {
             throws ZygoteInit.MethodAndArgsCaller {
         if (DEBUG) Slog.d(TAG, "RuntimeInit: Starting application from zygote");
 
+        Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "RuntimeInit");
         redirectLogStreams();
 
         commonInit();
         nativeZygoteInit();
-
         applicationInit(targetSdkVersion, argv, classLoader);
     }
 
@@ -318,6 +319,9 @@ public class RuntimeInit {
             return;
         }
 
+        // The end of of the RuntimeInit event (see #zygoteInit).
+        Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
+
         // Remaining arguments are passed to the start class's static main
         invokeStaticMain(args.startClass, args.startArgs, classLoader);
     }
diff --git a/core/java/com/android/internal/os/Zygote.java b/core/java/com/android/internal/os/Zygote.java
index 1e7ee5a..4f6d781 100644
--- a/core/java/com/android/internal/os/Zygote.java
+++ b/core/java/com/android/internal/os/Zygote.java
@@ -17,6 +17,7 @@
 package com.android.internal.os;
 
 
+import android.os.Trace;
 import dalvik.system.ZygoteHooks;
 import android.system.ErrnoException;
 import android.system.Os;
@@ -88,6 +89,13 @@ public final class Zygote {
         int pid = nativeForkAndSpecialize(
                   uid, gid, gids, debugFlags, rlimits, mountExternal, seInfo, niceName, fdsToClose,
                   instructionSet, appDataDir);
+        // Enable tracing as soon as possible for the child process.
+        if (pid == 0) {
+            Trace.setTracingEnabled(true);
+
+            // Note that this event ends at the end of handleChildProc,
+            Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "PostFork");
+        }
         VM_HOOKS.postForkCommon();
         return pid;
     }
@@ -124,6 +132,10 @@ public final class Zygote {
         VM_HOOKS.preFork();
         int pid = nativeForkSystemServer(
                 uid, gid, gids, debugFlags, rlimits, permittedCapabilities, effectiveCapabilities);
+        // Enable tracing as soon as we enter the system_server.
+        if (pid == 0) {
+            Trace.setTracingEnabled(true);
+        }
         VM_HOOKS.postForkCommon();
         return pid;
     }
diff --git a/core/java/com/android/internal/os/ZygoteConnection.java b/core/java/com/android/internal/os/ZygoteConnection.java
index 969d236..1a0345b 100644
--- a/core/java/com/android/internal/os/ZygoteConnection.java
+++ b/core/java/com/android/internal/os/ZygoteConnection.java
@@ -27,6 +27,7 @@ import android.net.LocalSocket;
 import android.os.Process;
 import android.os.SELinux;
 import android.os.SystemProperties;
+import android.os.Trace;
 import android.system.ErrnoException;
 import android.system.Os;
 import android.util.Log;
@@ -711,7 +712,6 @@ class ZygoteConnection {
     private void handleChildProc(Arguments parsedArgs,
             FileDescriptor[] descriptors, FileDescriptor pipeFd, PrintStream newStderr)
             throws ZygoteInit.MethodAndArgsCaller {
-
         /**
          * By the time we get here, the native code has closed the two actual Zygote
          * socket connections, and substituted /dev/null in their place.  The LocalSocket
@@ -740,6 +740,8 @@ class ZygoteConnection {
             Process.setArgV0(parsedArgs.niceName);
         }
 
+        // End of the postFork event.
+        Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
         if (parsedArgs.invokeWith != null) {
             WrapperInit.execApplication(parsedArgs.invokeWith,
                     parsedArgs.niceName, parsedArgs.targetSdkVersion,