State queue dump
Bug: 6591648
Change-Id: Iac75e5ea64e86640b3d890c46a636641b9733c6d
diff --git a/services/audioflinger/StateQueue.h b/services/audioflinger/StateQueue.h
index fe72ddc..eba190c 100644
--- a/services/audioflinger/StateQueue.h
+++ b/services/audioflinger/StateQueue.h
@@ -19,6 +19,34 @@
namespace android {
+#ifdef STATE_QUEUE_DUMP
+// The StateQueueObserverDump and StateQueueMutatorDump keep
+// a cache of StateQueue statistics that can be logged by dumpsys.
+// Each individual native word-sized field is accessed atomically. But the
+// overall structure is non-atomic, that is there may be an inconsistency between fields.
+// No barriers or locks are used for either writing or reading.
+// Only POD types are permitted, and the contents shouldn't be trusted (i.e. do range checks).
+// It has a different lifetime than the StateQueue, and so it can't be a member of StateQueue.
+
+struct StateQueueObserverDump {
+ StateQueueObserverDump() : mStateChanges(0) { }
+ /*virtual*/ ~StateQueueObserverDump() { }
+ unsigned mStateChanges; // incremented each time poll() detects a state change
+ void dump(int fd);
+};
+
+struct StateQueueMutatorDump {
+ StateQueueMutatorDump() : mPushDirty(0), mPushAck(0), mBlockedSequence(0) { }
+ /*virtual*/ ~StateQueueMutatorDump() { }
+ unsigned mPushDirty; // incremented each time push() is called with a dirty state
+ unsigned mPushAck; // incremented each time push(BLOCK_UNTIL_ACKED) is called
+ unsigned mBlockedSequence; // incremented before and after each time that push()
+ // blocks for more than one PUSH_BLOCK_ACK_NS;
+ // if odd, then mutator is currently blocked inside push()
+ void dump(int fd);
+};
+#endif
+
// manages a FIFO queue of states
template<typename T> class StateQueue {
@@ -69,6 +97,16 @@
// Return whether the current state is dirty (modified and not pushed).
bool isDirty() const { return mIsDirty; }
+#ifdef STATE_QUEUE_DUMP
+ // Register location of observer dump area
+ void setObserverDump(StateQueueObserverDump *dump)
+ { mObserverDump = dump != NULL ? dump : &mObserverDummyDump; }
+
+ // Register location of mutator dump area
+ void setMutatorDump(StateQueueMutatorDump *dump)
+ { mMutatorDump = dump != NULL ? dump : &mMutatorDummyDump; }
+#endif
+
private:
static const unsigned kN = 4; // values != 4 are not supported by this code
T mStates[kN]; // written by mutator, read by observer
@@ -87,6 +125,13 @@
bool mIsDirty; // whether mutating state has been modified since last push
bool mIsInitialized; // whether mutating state has been initialized yet
+#ifdef STATE_QUEUE_DUMP
+ StateQueueObserverDump mObserverDummyDump; // default area for observer dump if not set
+ StateQueueObserverDump* mObserverDump; // pointer to active observer dump, always non-NULL
+ StateQueueMutatorDump mMutatorDummyDump; // default area for mutator dump if not set
+ StateQueueMutatorDump* mMutatorDump; // pointer to active mutator dump, always non-NULL
+#endif
+
}; // class StateQueue
} // namespace android