diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index c3f08f6..593f131 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -227,7 +227,7 @@
     sp<NBLog::Writer>   newWriter_l(size_t size, const char *name);
     void                unregisterWriter(const sp<NBLog::Writer>& writer);
 private:
-    static const size_t kLogMemorySize = 10 * 1024;
+    static const size_t kLogMemorySize = 20 * 1024;
     sp<MemoryDealer>    mLogMemoryDealer;   // == 0 when NBLog is disabled
 public:
 
diff --git a/services/audioflinger/FastMixer.cpp b/services/audioflinger/FastMixer.cpp
index 80e37ca..467da39 100644
--- a/services/audioflinger/FastMixer.cpp
+++ b/services/audioflinger/FastMixer.cpp
@@ -301,6 +301,11 @@
                     const FastTrack* fastTrack = &current->mFastTracks[i];
                     AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider;
                     ALOG_ASSERT(bufferProvider != NULL && fastTrackNames[i] == -1);
+                    if (bufferProvider == NULL ||
+                            bufferProvider->getValid() != AudioBufferProvider::kValid) {
+                        logWriter->logTimestamp();
+                        logWriter->logf("added invalid %#x", i);
+                    }
                     if (mixer != NULL) {
                         // calling getTrackName with default channel mask and a random invalid
                         //   sessionId (no effects here)
@@ -335,6 +340,11 @@
                     if (fastTrack->mGeneration != generations[i]) {
                         AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider;
                         ALOG_ASSERT(bufferProvider != NULL);
+                        if (bufferProvider == NULL ||
+                                bufferProvider->getValid() != AudioBufferProvider::kValid) {
+                            logWriter->logTimestamp();
+                            logWriter->logf("modified invalid %#x", i);
+                        }
                         if (mixer != NULL) {
                             name = fastTrackNames[i];
                             ALOG_ASSERT(name >= 0);
@@ -423,6 +433,12 @@
                 }
                 ftDump->mUnderruns = underruns;
                 ftDump->mFramesReady = framesReady;
+                AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider;
+                if (bufferProvider == NULL ||
+                        bufferProvider->getValid() != AudioBufferProvider::kValid) {
+                    logWriter->logTimestamp();
+                    logWriter->logf("mixing invalid %#x", i);
+                }
             }
 
             int64_t pts;
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index ba848d7..8cc5f6c 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -1196,6 +1196,8 @@
 
     { // scope for mLock
         Mutex::Autolock _l(mLock);
+        mNBLogWriter->logf("createTrack_l isFast=%d caller=%d",
+                (*flags & IAudioFlinger::TRACK_FAST) != 0, IPCThreadState::self()->getCallingPid());
 
         // all tracks in same audio session must share the same routing strategy otherwise
         // conflicts will happen when tracks are moved from one output to another by audio policy
@@ -1249,7 +1251,6 @@
     if (status) {
         *status = lStatus;
     }
-    mNBLogWriter->logf("createTrack_l");
     return track;
 }
 
@@ -1317,7 +1318,8 @@
 // addTrack_l() must be called with ThreadBase::mLock held
 status_t AudioFlinger::PlaybackThread::addTrack_l(const sp<Track>& track)
 {
-    mNBLogWriter->logf("addTrack_l mName=%d", track->mName);
+    mNBLogWriter->logf("addTrack_l mName=%d mFastIndex=%d caller=%d", track->mName,
+            track->mFastIndex, IPCThreadState::self()->getCallingPid());
     status_t status = ALREADY_EXISTS;
 
     // set retry count for buffer fill
@@ -1351,7 +1353,9 @@
 // destroyTrack_l() must be called with ThreadBase::mLock held
 void AudioFlinger::PlaybackThread::destroyTrack_l(const sp<Track>& track)
 {
-    mNBLogWriter->logf("destroyTrack_l mName=%d", track->mName);
+    mNBLogWriter->logTimestamp();
+    mNBLogWriter->logf("destroyTrack_l mName=%d mFastIndex=%d mClientPid=%d", track->mName,
+            track->mFastIndex, track->mClient != 0 ? track->mClient->pid() : -1);
     track->mState = TrackBase::TERMINATED;
     // active tracks are removed by threadLoop()
     if (mActiveTracks.indexOf(track) < 0) {
@@ -1361,7 +1365,9 @@
 
 void AudioFlinger::PlaybackThread::removeTrack_l(const sp<Track>& track)
 {
-    mNBLogWriter->logf("removeTrack_l mName=%d", track->mName);
+    mNBLogWriter->logTimestamp();
+    mNBLogWriter->logf("removeTrack_l mName=%d mFastIndex=%d clientPid=%d", track->mName,
+            track->mFastIndex, track->mClient != 0 ? track->mClient->pid() : -1);
     track->triggerEvents(AudioSystem::SYNC_EVENT_PRESENTATION_COMPLETE);
     mTracks.remove(track);
     deleteTrackName_l(track->name());
@@ -2870,7 +2876,9 @@
     if (CC_UNLIKELY(count)) {
         for (size_t i=0 ; i<count ; i++) {
             const sp<Track>& track = tracksToRemove->itemAt(i);
-            mNBLogWriter->logf("prepareTracks_l remove name=%u", track->name());
+            mNBLogWriter->logTimestamp();
+            mNBLogWriter->logf("prepareTracks_l remove name=%u mFastIndex=%d", track->name(),
+                    track->mFastIndex);
             mActiveTracks.remove(track);
             if (track->mainBuffer() != mMixBuffer) {
                 chain = getEffectChain_l(track->sessionId());
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index fa1e336..8497788 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -315,7 +315,7 @@
                 // keyed by session ID, the second by type UUID timeLow field
                 KeyedVector< int, KeyedVector< int, sp<SuspendedSessionDesc> > >
                                         mSuspendedSessions;
-                static const size_t     kLogSize = 512;
+                static const size_t     kLogSize = 4096;
                 sp<NBLog::Writer>       mNBLogWriter;
 };
 
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index 315cbbc..f679751 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -351,6 +351,7 @@
             // Read the initial underruns because this field is never cleared by the fast mixer
             mObservedUnderruns = thread->getFastTrackUnderruns(i);
             thread->mFastTrackAvailMask &= ~(1 << i);
+            thread->mNBLogWriter->logf("new Track mName=%d mFastIndex=%d", mName, mFastIndex);
         }
     }
     ALOGV("Track constructor name %d, calling pid %d", mName,
@@ -360,6 +361,7 @@
 AudioFlinger::PlaybackThread::Track::~Track()
 {
     ALOGV("PlaybackThread::Track destructor");
+    // FIXME not sure if safe to log here, would need a lock on thread to do it
 }
 
 void AudioFlinger::PlaybackThread::Track::destroy()
@@ -569,7 +571,8 @@
     sp<ThreadBase> thread = mThread.promote();
     if (thread != 0) {
         Mutex::Autolock _l(thread->mLock);
-        thread->mNBLogWriter->logf("start mName=%d", mName);
+        thread->mNBLogWriter->logf("start mName=%d mFastIndex=%d caller=%d", mName, mFastIndex,
+                IPCThreadState::self()->getCallingPid());
         track_state state = mState;
         // here the track could be either new, or restarted
         // in both cases "unstop" the track
@@ -612,7 +615,8 @@
     sp<ThreadBase> thread = mThread.promote();
     if (thread != 0) {
         Mutex::Autolock _l(thread->mLock);
-        thread->mNBLogWriter->logf("stop mName=%d", mName);
+        thread->mNBLogWriter->logf("stop mName=%d mFastIndex=%d caller=%d", mName, mFastIndex,
+                IPCThreadState::self()->getCallingPid());
         track_state state = mState;
         if (state == RESUMING || state == ACTIVE || state == PAUSING || state == PAUSED) {
             // If the track is not active (PAUSED and buffers full), flush buffers
@@ -649,7 +653,8 @@
     sp<ThreadBase> thread = mThread.promote();
     if (thread != 0) {
         Mutex::Autolock _l(thread->mLock);
-        thread->mNBLogWriter->logf("pause mName=%d", mName);
+        thread->mNBLogWriter->logf("pause mName=%d mFastIndex=%d caller=%d", mName, mFastIndex,
+                IPCThreadState::self()->getCallingPid());
         if (mState == ACTIVE || mState == RESUMING) {
             mState = PAUSING;
             ALOGV("ACTIVE/RESUMING => PAUSING (%d) on thread %p", mName, thread.get());
@@ -673,7 +678,8 @@
     sp<ThreadBase> thread = mThread.promote();
     if (thread != 0) {
         Mutex::Autolock _l(thread->mLock);
-        thread->mNBLogWriter->logf("flush mName=%d", mName);
+        thread->mNBLogWriter->logf("flush mName=%d mFastIndex=%d caller=%d", mName, mFastIndex,
+                IPCThreadState::self()->getCallingPid());
         if (mState != STOPPING_1 && mState != STOPPING_2 && mState != STOPPED && mState != PAUSED &&
                 mState != PAUSING && mState != IDLE && mState != FLUSHED) {
             return;