Bug 888473 - Start GeckoJavaSampler early when profiling startup; r=BenWa

mobile/android/base/GeckoApp.java

@@ -1146,6 +1146,24 @@ abstract public class GeckoApp
         });
     }
 
+    /**
+     * Check and start the Java profiler if MOZ_PROFILER_STARTUP env var is specified
+     **/
+    protected void earlyStartJavaSampler(Intent intent)
+    {
+        String env = intent.getStringExtra("env0");
+        for (int i = 1; env != null; i++) {
+            if (env.startsWith("MOZ_PROFILER_STARTUP=")) {
+                if (!env.endsWith("=")) {
+                    GeckoJavaSampler.start(10, 1000);
+                    Log.d(LOGTAG, "Profiling Java on startup");
+                }
+                break;
+            }
+            env = intent.getStringExtra("env" + i);
+        }
+    }
+
     /**
      * Called when the activity is first created.
      *
@@ -1166,7 +1184,9 @@ abstract public class GeckoApp
         mJavaUiStartupTimer = new Telemetry.Timer("FENNEC_STARTUP_TIME_JAVAUI");
         mGeckoReadyStartupTimer = new Telemetry.Timer("FENNEC_STARTUP_TIME_GECKOREADY");
 
-        String args = getIntent().getStringExtra("args");
+        Intent intent = getIntent();
+        String args = intent.getStringExtra("args");
+        earlyStartJavaSampler(intent);
 
         String profileName = null;
         String profilePath = null;

mobile/android/base/GeckoJavaSampler.java

@@ -5,6 +5,7 @@
 
 package org.mozilla.gecko;
 
+import android.os.SystemClock;
 import android.util.Log;
 import java.lang.Thread;
 import java.util.HashMap;
@@ -16,6 +17,7 @@ public class GeckoJavaSampler {
     private static Thread sSamplingThread = null;
     private static SamplingThread sSamplingRunnable = null;
     private static Thread sMainThread = null;
+    private static volatile boolean sLibsLoaded = false;
 
     // Use the same timer primitive as the profiler
     // to get a perfect sample syncing.
@@ -24,9 +26,17 @@ public class GeckoJavaSampler {
     private static class Sample {
         public Frame[] mFrames;
         public double mTime;
+        public long mJavaTime; // non-zero if Android system time is used
         public Sample(StackTraceElement[] aStack) {
             mFrames = new Frame[aStack.length];
+            if (sLibsLoaded) {
                 mTime = getProfilerTime();
+            }
+            if (mTime == 0.0d) {
+                // getProfilerTime is not available yet; either libs are not loaded,
+                // or profiling hasn't started on the Gecko side yet
+                mJavaTime = SystemClock.elapsedRealtime();
+            }
             for (int i = 0; i < aStack.length; i++) {
                 mFrames[aStack.length - 1 - i] = new Frame();
                 mFrames[aStack.length - 1 - i].fileName = aStack[i].getFileName();
@@ -122,9 +132,14 @@ public class GeckoJavaSampler {
     private synchronized static Sample getSample(int aThreadId, int aSampleId) {
         return sSamplingRunnable.getSample(aThreadId, aSampleId);
     }
+
     public synchronized static double getSampleTime(int aThreadId, int aSampleId) {
         Sample sample = getSample(aThreadId, aSampleId);
         if (sample != null) {
+            if (sample.mJavaTime != 0) {
+                return (double)(sample.mJavaTime -
+                    SystemClock.elapsedRealtime()) + getProfilerTime();
+            }
             System.out.println("Sample: " + sample.mTime);
             return sample.mTime;
         }
@@ -144,6 +159,9 @@ public class GeckoJavaSampler {
 
     public static void start(int aInterval, int aSamples) {
         synchronized (GeckoJavaSampler.class) {
+            if (sSamplingRunnable != null) {
+                return;
+            }
             sSamplingRunnable = new SamplingThread(aInterval, aSamples);
             sSamplingThread = new Thread(sSamplingRunnable, "Java Sampler");
             sSamplingThread.start();
@@ -178,6 +196,10 @@ public class GeckoJavaSampler {
             sSamplingRunnable = null;
         }
     }
+
+    public static void setLibsLoaded() {
+        sLibsLoaded = true;
+    }
 }
 
 

mobile/android/base/GeckoThread.java

@@ -76,6 +76,7 @@ public class GeckoThread extends Thread implements GeckoEventListener {
         GeckoLoader.loadSQLiteLibs(app, resourcePath);
         GeckoLoader.loadNSSLibs(app, resourcePath);
         GeckoLoader.loadGeckoLibs(app, resourcePath);
+        GeckoJavaSampler.setLibsLoaded();
 
         Locale.setDefault(locale);
 

tools/profiler/platform.cpp

@@ -300,6 +300,9 @@ void mozilla_sampler_init(void* stackTop)
                          , "leaf"
 #if defined(XP_WIN) || defined(XP_MACOSX)
                          , "stackwalk"
+#endif
+#if defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)
+                         , "java"
 #endif
                          };
   profiler_start(PROFILE_DEFAULT_ENTRY, PROFILE_DEFAULT_INTERVAL,
@@ -605,6 +608,9 @@ void mozilla_sampler_unregister_thread()
 
 double mozilla_sampler_time()
 {
+  if (!mozilla_sampler_is_active()) {
+    return 0.0;
+  }
   TimeDuration delta = TimeStamp::Now() - sStartTime;
   return delta.ToMilliseconds();
 }