Automatically trace messages on shared loopers.
There are a handful of looper threads in the system_process that
are shared by dozens of different internal services. To help track
down what these operations are, tag the processing of each message
with a string that tries describing where it originated from: the
class name of the Handler, and the message number or class name of the
Runnable.
Bug: 28046299
Change-Id: I409ec43fea8daaae4fd70df05d4fed929a7249ae
diff --git a/core/java/android/os/Looper.java b/core/java/android/os/Looper.java
index 34c880f..b58ff1f 100644
--- a/core/java/android/os/Looper.java
+++ b/core/java/android/os/Looper.java
@@ -72,6 +72,7 @@
final Thread mThread;
private Printer mLogging;
+ private long mTraceTag;
/** Initialize the current thread as a looper.
* This gives you a chance to create handlers that then reference
@@ -139,13 +140,23 @@
}
// This must be in a local variable, in case a UI event sets the logger
- Printer logging = me.mLogging;
+ final Printer logging = me.mLogging;
if (logging != null) {
logging.println(">>>>> Dispatching to " + msg.target + " " +
msg.callback + ": " + msg.what);
}
- msg.target.dispatchMessage(msg);
+ final long traceTag = me.mTraceTag;
+ if (traceTag != 0) {
+ Trace.traceBegin(traceTag, msg.target.getTraceName(msg));
+ }
+ try {
+ msg.target.dispatchMessage(msg);
+ } finally {
+ if (traceTag != 0) {
+ Trace.traceEnd(traceTag);
+ }
+ }
if (logging != null) {
logging.println("<<<<< Finished to " + msg.target + " " + msg.callback);
@@ -208,6 +219,11 @@
mLogging = printer;
}
+ /** {@hide} */
+ public void setTraceTag(long traceTag) {
+ mTraceTag = traceTag;
+ }
+
/**
* Quits the looper.
* <p>