diff --git a/services/core/java/com/android/server/DisplayThread.java b/services/core/java/com/android/server/DisplayThread.java
index aa0a805..9ef0259 100644
--- a/services/core/java/com/android/server/DisplayThread.java
+++ b/services/core/java/com/android/server/DisplayThread.java
@@ -17,6 +17,7 @@
 package com.android.server;
 
 import android.os.Handler;
+import android.os.Trace;
 
 /**
  * Shared singleton foreground thread for the system.  This is a thread for
@@ -36,6 +37,7 @@
         if (sInstance == null) {
             sInstance = new DisplayThread();
             sInstance.start();
+            sInstance.getLooper().setTraceTag(Trace.TRACE_TAG_ACTIVITY_MANAGER);
             sHandler = new Handler(sInstance.getLooper());
         }
     }
diff --git a/services/core/java/com/android/server/FgThread.java b/services/core/java/com/android/server/FgThread.java
index 03765db..5f85cba 100644
--- a/services/core/java/com/android/server/FgThread.java
+++ b/services/core/java/com/android/server/FgThread.java
@@ -17,6 +17,7 @@
 package com.android.server;
 
 import android.os.Handler;
+import android.os.Trace;
 
 /**
  * Shared singleton foreground thread for the system.  This is a thread for regular
@@ -38,6 +39,7 @@
         if (sInstance == null) {
             sInstance = new FgThread();
             sInstance.start();
+            sInstance.getLooper().setTraceTag(Trace.TRACE_TAG_ACTIVITY_MANAGER);
             sHandler = new Handler(sInstance.getLooper());
         }
     }
diff --git a/services/core/java/com/android/server/IoThread.java b/services/core/java/com/android/server/IoThread.java
index 0f29857..ad4c194 100644
--- a/services/core/java/com/android/server/IoThread.java
+++ b/services/core/java/com/android/server/IoThread.java
@@ -17,6 +17,7 @@
 package com.android.server;
 
 import android.os.Handler;
+import android.os.Trace;
 
 /**
  * Shared singleton I/O thread for the system.  This is a thread for non-background
@@ -35,6 +36,7 @@
         if (sInstance == null) {
             sInstance = new IoThread();
             sInstance.start();
+            sInstance.getLooper().setTraceTag(Trace.TRACE_TAG_ACTIVITY_MANAGER);
             sHandler = new Handler(sInstance.getLooper());
         }
     }
diff --git a/services/core/java/com/android/server/UiThread.java b/services/core/java/com/android/server/UiThread.java
index 0beb77f..c06afc2 100644
--- a/services/core/java/com/android/server/UiThread.java
+++ b/services/core/java/com/android/server/UiThread.java
@@ -17,6 +17,7 @@
 package com.android.server;
 
 import android.os.Handler;
+import android.os.Trace;
 
 /**
  * Shared singleton thread for showing UI.  This is a foreground thread, and in
@@ -35,6 +36,7 @@
         if (sInstance == null) {
             sInstance = new UiThread();
             sInstance.start();
+            sInstance.getLooper().setTraceTag(Trace.TRACE_TAG_ACTIVITY_MANAGER);
             sHandler = new Handler(sInstance.getLooper());
         }
     }