Index: base/android/java/src/org/chromium/base/SystemMessageHandler.java |
diff --git a/base/android/java/src/org/chromium/base/SystemMessageHandler.java b/base/android/java/src/org/chromium/base/SystemMessageHandler.java |
index e1fbb0f4bed9538212313fdb374e81f0ac37f414..cd64c858f095fdb4c8e9d9fceb59408ff95155bd 100644 |
--- a/base/android/java/src/org/chromium/base/SystemMessageHandler.java |
+++ b/base/android/java/src/org/chromium/base/SystemMessageHandler.java |
@@ -6,9 +6,17 @@ package org.chromium.base; |
import android.os.Handler; |
import android.os.Message; |
+import android.os.MessageQueue; |
+import android.util.Log; |
+ |
+import java.lang.reflect.Field; |
+import java.lang.reflect.InvocationTargetException; |
+import java.lang.reflect.Method; |
class SystemMessageHandler extends Handler { |
+ private static final String TAG = "SystemMessageHandler"; |
+ |
private static final int SCHEDULED_WORK = 1; |
private static final int DELAYED_SCHEDULED_WORK = 2; |
@@ -16,12 +24,23 @@ class SystemMessageHandler extends Handler { |
private long mMessagePumpDelegateNative = 0; |
private long mDelayedScheduledTimeTicks = 0; |
+ // The following members are used to detect and trace the presence of sync |
+ // barriers in Android's MessageQueue. Note that this detection is |
+ // experimental, temporary and intended only for diagnostic purposes. |
+ private MessageQueue mMessageQueue; |
+ private Field mMessageQueueMessageField; |
+ private Field mMessageTargetField; |
+ private boolean mQueueHasSyncBarrier; |
+ private long mSyncBarrierTraceId; |
+ |
private SystemMessageHandler(long messagePumpDelegateNative) { |
mMessagePumpDelegateNative = messagePumpDelegateNative; |
- } |
+ tryEnableSyncBarrierDetection(); |
+ } |
@Override |
public void handleMessage(Message msg) { |
+ updateWhetherQueueHasBlockingSyncBarrier(); |
if (msg.what == DELAYED_SCHEDULED_WORK) { |
mDelayedScheduledTimeTicks = 0; |
} |
@@ -31,6 +50,8 @@ class SystemMessageHandler extends Handler { |
@SuppressWarnings("unused") |
@CalledByNative |
private void scheduleWork() { |
+ updateWhetherQueueHasBlockingSyncBarrier(); |
+ if (mQueueHasSyncBarrier) TraceEvent.instant("SystemMessageHandler:immediateWorkBlocked"); |
sendEmptyMessage(SCHEDULED_WORK); |
} |
@@ -41,16 +62,101 @@ class SystemMessageHandler extends Handler { |
removeMessages(DELAYED_SCHEDULED_WORK); |
} |
mDelayedScheduledTimeTicks = delayedTimeTicks; |
+ updateWhetherQueueHasBlockingSyncBarrier(); |
+ if (mQueueHasSyncBarrier) TraceEvent.instant("SystemMessageHandler:delayedWorkBlocked"); |
sendEmptyMessageDelayed(DELAYED_SCHEDULED_WORK, millis); |
} |
@SuppressWarnings("unused") |
@CalledByNative |
private void removeAllPendingMessages() { |
+ updateWhetherQueueHasBlockingSyncBarrier(); |
removeMessages(SCHEDULED_WORK); |
removeMessages(DELAYED_SCHEDULED_WORK); |
} |
+ private void updateWhetherQueueHasBlockingSyncBarrier() { |
+ if (mMessageQueue == null) return; |
+ // As barrier detection is only used for tracing, early out when tracing |
+ // is disabled to avoid any potential performance penalties. |
+ if (!TraceEvent.enabled()) { |
+ mQueueHasSyncBarrier = false; |
+ return; |
+ } |
+ final Message queueHead = (Message)getField(mMessageQueue, mMessageQueueMessageField); |
nyquist
2014/09/23 00:08:39
These final qualifiers are unnecessary I believe.
jdduke (slow)
2014/09/23 16:20:46
Done.
|
+ final boolean queueHasSyncbarrier = isSyncBarrierMessage(queueHead); |
nyquist
2014/09/23 00:08:38
queueHasSyncBarrier
jdduke (slow)
2014/09/23 16:20:46
Done.
|
+ setQueueHasSyncBarrier(queueHasSyncbarrier); |
+ } |
+ |
+ private boolean isSyncBarrierMessage(Message message) { |
+ if (message == null) return false; |
+ // Sync barrier messages have null targets. |
+ return getField(message, mMessageTargetField) == null; |
+ } |
+ |
+ private void tryEnableSyncBarrierDetection() { |
+ assert mMessageQueue == null; |
+ |
+ boolean success = false; |
+ try { |
+ Class<?> looperClass = Class.forName("android.os.Looper"); |
+ Method getQueueMethod = looperClass.getMethod("getQueue", new Class[]{}); |
+ mMessageQueue = (MessageQueue)(getQueueMethod.invoke(getLooper())); |
nyquist
2014/09/23 00:08:38
Just (MessageQueue) getQueueMethod.invoke(getLoope
jdduke (slow)
2014/09/23 16:20:46
Done.
|
+ |
+ mMessageQueueMessageField = mMessageQueue.getClass().getDeclaredField("mMessages"); |
+ mMessageQueueMessageField.setAccessible(true); |
+ |
+ mMessageTargetField = new Message().getClass().getDeclaredField("target"); |
nyquist
2014/09/23 00:08:38
Could this just be Message.class.getDeclaredField(
jdduke (slow)
2014/09/23 16:20:46
Done.
|
+ mMessageTargetField.setAccessible(true); |
+ |
+ mSyncBarrierTraceId = hashCode(); |
+ |
+ success = true; |
+ } catch (ClassNotFoundException e) { |
+ Log.e(TAG, "Failed to find class: " + e); |
+ } catch (NoSuchMethodException e) { |
+ Log.e(TAG, "Failed to load method: " + e); |
+ } catch (NoSuchFieldException e) { |
+ Log.e(TAG, "Failed to load field: " + e); |
+ } catch (InvocationTargetException e) { |
+ Log.e(TAG, "Failed invocation: " + e); |
+ } catch (IllegalAccessException e) { |
+ Log.e(TAG, "Illegal access to reflected invocation: " + e); |
+ } catch (RuntimeException e) { |
nyquist
2014/09/23 00:08:39
This is masking IllegalArgumentException thrown by
jdduke (slow)
2014/09/23 16:20:46
Not intentional, good catch.
|
+ Log.e(TAG, e.toString()); |
+ } finally { |
+ if (!success) disableSyncBarrierDetection(); |
+ } |
+ } |
+ |
+ private void disableSyncBarrierDetection() { |
+ Log.e(TAG, "Unexpected error with sync barrier detection, disabling."); |
+ mMessageQueue = null; |
+ mMessageQueueMessageField = null; |
+ mMessageTargetField = null; |
+ setQueueHasSyncBarrier(false); |
+ } |
+ |
+ private void setQueueHasSyncBarrier(boolean queueHasSyncbarrier) { |
nyquist
2014/09/23 00:08:39
queueHasSyncBarrier
jdduke (slow)
2014/09/23 16:20:46
Done.
|
+ if (queueHasSyncbarrier == mQueueHasSyncBarrier) return; |
+ mQueueHasSyncBarrier = queueHasSyncbarrier; |
+ if (mQueueHasSyncBarrier) { |
+ TraceEvent.startAsync("SyncBarrier", mSyncBarrierTraceId); |
+ } else { |
+ TraceEvent.finishAsync("SyncBarrier", mSyncBarrierTraceId); |
+ } |
+ } |
+ |
+ private Object getField(Object object, Field field) { |
+ try { |
+ return field.get(object); |
+ } catch (IllegalAccessException e) { |
+ Log.e(TAG, "Failed field access: " + e); |
+ disableSyncBarrierDetection(); |
+ } |
+ return null; |
+ } |
+ |
@CalledByNative |
private static SystemMessageHandler create(long messagePumpDelegateNative) { |
return new SystemMessageHandler(messagePumpDelegateNative); |