I was seeing lots of stack traces of people hung for noticeable
amounts of time when switching between activities.
e.g. On of the common gmail stacks showing this pause was:
android.os.StrictMode$StrictModeDiskWriteViolation: policy=391 violation=1
at android.os.StrictMode$AndroidBlockGuardPolicy.startHandlingViolationException(StrictMode.java:272)
at android.os.StrictMode$AndroidBlockGuardPolicy.onWriteToDisk(StrictMode.java:243)
at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:238)
at java.io.FileOutputStream.<init>(FileOutputStream.java:97)
at java.io.FileOutputStream.<init>(FileOutputStream.java:69)
at com.android.server.am.UsageStatsService.writeStatsFLOCK(UsageStatsService.java:424)
at com.android.server.am.UsageStatsService.writeStatsToFile(UsageStatsService.java:398)
at com.android.server.am.UsageStatsService.notePauseComponent(UsageStatsService.java:539)
at com.android.server.am.ActivityManagerService.updateUsageStats(ActivityManagerService.java:1856)
at com.android.server.am.ActivityStack.startPausingLocked(ActivityStack.java:667)
at com.android.server.am.ActivityStack.finishActivityLocked(ActivityStack.java:2925)
at com.android.server.am.ActivityStack.requestFinishActivityLocked(ActivityStack.java:2836)
at com.android.server.am.ActivityManagerService.finishActivity(ActivityManagerService.java:2276)
at android.app.ActivityManagerNative.onTransact(ActivityManagerNative.java:237)
at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:1415)
at android.os.Binder.execTransact(Binder.java:320)
at dalvik.system.NativeStart.run(Native Method)
at android.app.ActivityManagerProxy.finishActivity(ActivityManagerNative.java:1454)
at android.app.Activity.finish(Activity.java:3260)
at android.app.Activity.onBackPressed(Activity.java:1929)
at android.app.Activity.onKeyUp(Activity.java:1907)
at android.view.KeyEvent.dispatch(KeyEvent.java:1088)
at android.app.Activity.dispatchKeyEvent(Activity.java:2087)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1661)
at android.view.ViewRoot.deliverKeyEventToViewHierarchy(ViewRoot.java:2543)
at android.view.ViewRoot.handleFinishedEvent(ViewRoot.java:2516)
at android.view.ViewRoot.handleMessage(ViewRoot.java:1866)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:3609)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
at dalvik.system.NativeStart.main(Native Method)
Change-Id: Id49157bc635017292eaefddc5e22d73f5f4ab05e
389a916769