diff --git a/include/media/IMediaLogService.h b/include/media/IMediaLogService.h
new file mode 100644
index 0000000..1f5777e
--- /dev/null
+++ b/include/media/IMediaLogService.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_IMEDIALOGSERVICE_H
+#define ANDROID_IMEDIALOGSERVICE_H
+
+#include <binder/IInterface.h>
+#include <binder/IMemory.h>
+#include <binder/Parcel.h>
+
+namespace android {
+
+class IMediaLogService: public IInterface
+{
+public:
+    DECLARE_META_INTERFACE(MediaLogService);
+
+    virtual void    registerWriter(const sp<IMemory>& shared, size_t size, const char *name) = 0;
+    virtual void    unregisterWriter(const sp<IMemory>& shared) = 0;
+
+};
+
+class BnMediaLogService: public BnInterface<IMediaLogService>
+{
+public:
+    virtual status_t    onTransact(uint32_t code, const Parcel& data, Parcel* reply,
+                                uint32_t flags = 0);
+};
+
+}   // namespace android
+
+#endif  // ANDROID_IMEDIALOGSERVICE_H
diff --git a/media/libmedia/Android.mk b/media/libmedia/Android.mk
index a35d562..52fa3e1 100644
--- a/media/libmedia/Android.mk
+++ b/media/libmedia/Android.mk
@@ -23,6 +23,7 @@
     AudioRecord.cpp \
     AudioSystem.cpp \
     mediaplayer.cpp \
+    IMediaLogService.cpp \
     IMediaPlayerService.cpp \
     IMediaPlayerClient.cpp \
     IMediaRecorderClient.cpp \
diff --git a/media/libmedia/IMediaLogService.cpp b/media/libmedia/IMediaLogService.cpp
new file mode 100644
index 0000000..33239a7
--- /dev/null
+++ b/media/libmedia/IMediaLogService.cpp
@@ -0,0 +1,94 @@
+/*
+**
+** Copyright 2007, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+#define LOG_TAG "IMediaLogService"
+//#define LOG_NDEBUG 0
+
+#include <utils/Log.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <binder/Parcel.h>
+#include <media/IMediaLogService.h>
+
+namespace android {
+
+enum {
+    REGISTER_WRITER = IBinder::FIRST_CALL_TRANSACTION,
+    UNREGISTER_WRITER,
+};
+
+class BpMediaLogService : public BpInterface<IMediaLogService>
+{
+public:
+    BpMediaLogService(const sp<IBinder>& impl)
+        : BpInterface<IMediaLogService>(impl)
+    {
+    }
+
+    virtual void    registerWriter(const sp<IMemory>& shared, size_t size, const char *name) {
+        Parcel data, reply;
+        data.writeInterfaceToken(IMediaLogService::getInterfaceDescriptor());
+        data.writeStrongBinder(shared->asBinder());
+        data.writeInt32((int32_t) size);
+        data.writeCString(name);
+        status_t status = remote()->transact(REGISTER_WRITER, data, &reply);
+        // FIXME ignores status
+    }
+
+    virtual void    unregisterWriter(const sp<IMemory>& shared) {
+        Parcel data, reply;
+        data.writeInterfaceToken(IMediaLogService::getInterfaceDescriptor());
+        data.writeStrongBinder(shared->asBinder());
+        status_t status = remote()->transact(UNREGISTER_WRITER, data, &reply);
+        // FIXME ignores status
+    }
+
+};
+
+IMPLEMENT_META_INTERFACE(MediaLogService, "android.media.IMediaLogService");
+
+// ----------------------------------------------------------------------
+
+status_t BnMediaLogService::onTransact(
+    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
+{
+    switch (code) {
+
+        case REGISTER_WRITER: {
+            CHECK_INTERFACE(IMediaLogService, data, reply);
+            sp<IMemory> shared = interface_cast<IMemory>(data.readStrongBinder());
+            size_t size = (size_t) data.readInt32();
+            const char *name = data.readCString();
+            registerWriter(shared, size, name);
+            return NO_ERROR;
+        }
+
+        case UNREGISTER_WRITER: {
+            CHECK_INTERFACE(IMediaLogService, data, reply);
+            sp<IMemory> shared = interface_cast<IMemory>(data.readStrongBinder());
+            unregisterWriter(shared);
+            return NO_ERROR;
+        }
+
+        default:
+            return BBinder::onTransact(code, data, reply, flags);
+    }
+}
+
+// ----------------------------------------------------------------------------
+
+}; // namespace android
diff --git a/media/mediaserver/Android.mk b/media/mediaserver/Android.mk
index 8c3cc5e..0a0f4db 100644
--- a/media/mediaserver/Android.mk
+++ b/media/mediaserver/Android.mk
@@ -7,12 +7,17 @@
 LOCAL_SHARED_LIBRARIES := \
 	libaudioflinger \
 	libcameraservice \
+	libmedialogservice \
+	libcutils \
+	libnbaio \
+	libmedia \
 	libmediaplayerservice \
 	libutils \
 	libbinder
 
 LOCAL_C_INCLUDES := \
     frameworks/av/media/libmediaplayerservice \
+    frameworks/av/services/medialog \
     frameworks/av/services/audioflinger \
     frameworks/av/services/camera/libcameraservice
 
diff --git a/media/mediaserver/main_mediaserver.cpp b/media/mediaserver/main_mediaserver.cpp
index ddd5b84..0862952 100644
--- a/media/mediaserver/main_mediaserver.cpp
+++ b/media/mediaserver/main_mediaserver.cpp
@@ -18,14 +18,19 @@
 #define LOG_TAG "mediaserver"
 //#define LOG_NDEBUG 0
 
+#include <fcntl.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
 #include <binder/IPCThreadState.h>
 #include <binder/ProcessState.h>
 #include <binder/IServiceManager.h>
+#include <cutils/properties.h>
 #include <utils/Log.h>
 
 // from LOCAL_C_INCLUDES
 #include "AudioFlinger.h"
 #include "CameraService.h"
+#include "MediaLogService.h"
 #include "MediaPlayerService.h"
 #include "AudioPolicyService.h"
 
@@ -34,13 +39,95 @@
 int main(int argc, char** argv)
 {
     signal(SIGPIPE, SIG_IGN);
-    sp<ProcessState> proc(ProcessState::self());
-    sp<IServiceManager> sm = defaultServiceManager();
-    ALOGI("ServiceManager: %p", sm.get());
-    AudioFlinger::instantiate();
-    MediaPlayerService::instantiate();
-    CameraService::instantiate();
-    AudioPolicyService::instantiate();
-    ProcessState::self()->startThreadPool();
-    IPCThreadState::self()->joinThreadPool();
+    char value[PROPERTY_VALUE_MAX];
+    bool doLog = (property_get("ro.test_harness", value, "0") > 0) && (atoi(value) == 1);
+    pid_t childPid;
+    // FIXME The advantage of making the process containing media.log service the parent process of
+    // the process that contains all the other real services, is that it allows us to collect more
+    // detailed information such as signal numbers, stop and continue, resource usage, etc.
+    // But it is also more complex.  Consider replacing this by independent processes, and using
+    // binder on death notification instead.
+    if (doLog && (childPid = fork()) != 0) {
+        // media.log service
+        //prctl(PR_SET_NAME, (unsigned long) "media.log", 0, 0, 0);
+        // unfortunately ps ignores PR_SET_NAME for the main thread, so use this ugly hack
+        strcpy(argv[0], "media.log");
+        sp<ProcessState> proc(ProcessState::self());
+        MediaLogService::instantiate();
+        ProcessState::self()->startThreadPool();
+        for (;;) {
+            siginfo_t info;
+            int ret = waitid(P_PID, childPid, &info, WEXITED | WSTOPPED | WCONTINUED);
+            if (ret == EINTR) {
+                continue;
+            }
+            if (ret < 0) {
+                break;
+            }
+            char buffer[32];
+            const char *code;
+            switch (info.si_code) {
+            case CLD_EXITED:
+                code = "CLD_EXITED";
+                break;
+            case CLD_KILLED:
+                code = "CLD_KILLED";
+                break;
+            case CLD_DUMPED:
+                code = "CLD_DUMPED";
+                break;
+            case CLD_STOPPED:
+                code = "CLD_STOPPED";
+                break;
+            case CLD_TRAPPED:
+                code = "CLD_TRAPPED";
+                break;
+            case CLD_CONTINUED:
+                code = "CLD_CONTINUED";
+                break;
+            default:
+                snprintf(buffer, sizeof(buffer), "unknown (%d)", info.si_code);
+                code = buffer;
+                break;
+            }
+            struct rusage usage;
+            getrusage(RUSAGE_CHILDREN, &usage);
+            ALOG(LOG_ERROR, "media.log", "pid %d status %d code %s user %ld.%03lds sys %ld.%03lds",
+                    info.si_pid, info.si_status, code,
+                    usage.ru_utime.tv_sec, usage.ru_utime.tv_usec / 1000,
+                    usage.ru_stime.tv_sec, usage.ru_stime.tv_usec / 1000);
+            sp<IServiceManager> sm = defaultServiceManager();
+            sp<IBinder> binder = sm->getService(String16("media.log"));
+            if (binder != 0) {
+                Vector<String16> args;
+                binder->dump(-1, args);
+            }
+            switch (info.si_code) {
+            case CLD_EXITED:
+            case CLD_KILLED:
+            case CLD_DUMPED: {
+                ALOG(LOG_INFO, "media.log", "exiting");
+                _exit(0);
+                // not reached
+                }
+            default:
+                break;
+            }
+        }
+    } else {
+        // all other services
+        if (doLog) {
+            prctl(PR_SET_PDEATHSIG, SIGKILL);   // if parent media.log dies before me, kill me also
+            setpgid(0, 0);                      // but if I die first, don't kill my parent
+        }
+        sp<ProcessState> proc(ProcessState::self());
+        sp<IServiceManager> sm = defaultServiceManager();
+        ALOGI("ServiceManager: %p", sm.get());
+        AudioFlinger::instantiate();
+        MediaPlayerService::instantiate();
+        CameraService::instantiate();
+        AudioPolicyService::instantiate();
+        ProcessState::self()->startThreadPool();
+        IPCThreadState::self()->joinThreadPool();
+    }
 }
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 5f5b041..52fa576 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -59,6 +59,8 @@
 #include <common_time/cc_helper.h>
 //#include <common_time/local_clock.h>
 
+#include <media/IMediaLogService.h>
+
 // ----------------------------------------------------------------------------
 
 // Note: the following macro is used for extremely verbose logging message.  In
@@ -127,6 +129,11 @@
       mMode(AUDIO_MODE_INVALID),
       mBtNrecIsOff(false)
 {
+    char value[PROPERTY_VALUE_MAX];
+    bool doLog = (property_get("ro.test_harness", value, "0") > 0) && (atoi(value) == 1);
+    if (doLog) {
+        mLogMemoryDealer = new MemoryDealer(kLogMemorySize, "LogWriters");
+    }
 }
 
 void AudioFlinger::onFirstRef()
@@ -323,6 +330,17 @@
         if (locked) {
             mLock.unlock();
         }
+
+        // append a copy of media.log here by forwarding fd to it, but don't attempt
+        // to lookup the service if it's not running, as it will block for a second
+        if (mLogMemoryDealer != 0) {
+            sp<IBinder> binder = defaultServiceManager()->getService(String16("media.log"));
+            if (binder != 0) {
+                fdprintf(fd, "\nmedia.log:\n");
+                Vector<String16> args;
+                binder->dump(fd, args);
+            }
+        }
     }
     return NO_ERROR;
 }
@@ -340,6 +358,35 @@
     return client;
 }
 
+sp<NBLog::Writer> AudioFlinger::newWriter_l(size_t size, const char *name)
+{
+    if (mLogMemoryDealer == 0) {
+        return new NBLog::Writer();
+    }
+    sp<IMemory> shared = mLogMemoryDealer->allocate(NBLog::Timeline::sharedSize(size));
+    sp<NBLog::Writer> writer = new NBLog::Writer(size, shared);
+    sp<IBinder> binder = defaultServiceManager()->getService(String16("media.log"));
+    if (binder != 0) {
+        interface_cast<IMediaLogService>(binder)->registerWriter(shared, size, name);
+    }
+    return writer;
+}
+
+void AudioFlinger::unregisterWriter(const sp<NBLog::Writer>& writer)
+{
+    sp<IMemory> iMemory(writer->getIMemory());
+    if (iMemory == 0) {
+        return;
+    }
+    sp<IBinder> binder = defaultServiceManager()->getService(String16("media.log"));
+    if (binder != 0) {
+        interface_cast<IMediaLogService>(binder)->unregisterWriter(iMemory);
+        // Now the media.log remote reference to IMemory is gone.
+        // When our last local reference to IMemory also drops to zero,
+        // the IMemory destructor will deallocate the region from mMemoryDealer.
+    }
+}
+
 // IAudioFlinger interface
 
 
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index a7f5b9e..c3f08f6 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -53,6 +53,8 @@
 
 #include <powermanager/IPowerManager.h>
 
+#include <media/nbaio/NBLog.h>
+
 namespace android {
 
 class audio_track_cblk_t;
@@ -222,6 +224,13 @@
 
     // end of IAudioFlinger interface
 
+    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;
+    sp<MemoryDealer>    mLogMemoryDealer;   // == 0 when NBLog is disabled
+public:
+
     class SyncEvent;
 
     typedef void (*sync_event_callback_t)(const wp<SyncEvent>& event) ;
diff --git a/services/audioflinger/FastMixer.cpp b/services/audioflinger/FastMixer.cpp
index 9283f53..80e37ca 100644
--- a/services/audioflinger/FastMixer.cpp
+++ b/services/audioflinger/FastMixer.cpp
@@ -92,6 +92,7 @@
     struct timespec measuredWarmupTs = {0, 0};  // how long did it take for warmup to complete
     uint32_t warmupCycles = 0;  // counter of number of loop cycles required to warmup
     NBAIO_Sink* teeSink = NULL; // if non-NULL, then duplicate write() to this non-blocking sink
+    NBLog::Writer dummyLogWriter, *logWriter = &dummyLogWriter;
 
     for (;;) {
 
@@ -119,9 +120,12 @@
         FastMixerState::Command command = next->mCommand;
         if (next != current) {
 
+            logWriter->log("next != current");
+
             // As soon as possible of learning of a new dump area, start using it
             dumpState = next->mDumpState != NULL ? next->mDumpState : &dummyDumpState;
             teeSink = next->mTeeSink;
+            logWriter = next->mNBLogWriter != NULL ? next->mNBLogWriter : &dummyLogWriter;
 
             // We want to always have a valid reference to the previous (non-idle) state.
             // However, the state queue only guarantees access to current and previous states.
@@ -163,6 +167,7 @@
                 ALOG_ASSERT(coldFutexAddr != NULL);
                 int32_t old = android_atomic_dec(coldFutexAddr);
                 if (old <= 0) {
+                    logWriter->log("wait");
                     __futex_syscall4(coldFutexAddr, FUTEX_WAIT_PRIVATE, old - 1, NULL);
                 }
                 // This may be overly conservative; there could be times that the normal mixer
@@ -181,6 +186,7 @@
             }
             continue;
         case FastMixerState::EXIT:
+            logWriter->log("exit");
             delete mixer;
             delete[] mixBuffer;
             return false;
@@ -258,11 +264,15 @@
             unsigned currentTrackMask = current->mTrackMask;
             dumpState->mTrackMask = currentTrackMask;
             if (current->mFastTracksGen != fastTracksGen) {
+                logWriter->logf("gen %d", current->mFastTracksGen);
                 ALOG_ASSERT(mixBuffer != NULL);
                 int name;
 
                 // process removed tracks first to avoid running out of track names
                 unsigned removedTracks = previousTrackMask & ~currentTrackMask;
+                if (removedTracks) {
+                    logWriter->logf("removed %#x", removedTracks);
+                }
                 while (removedTracks != 0) {
                     i = __builtin_ctz(removedTracks);
                     removedTracks &= ~(1 << i);
@@ -282,6 +292,9 @@
 
                 // now process added tracks
                 unsigned addedTracks = currentTrackMask & ~previousTrackMask;
+                if (addedTracks) {
+                    logWriter->logf("added %#x", addedTracks);
+                }
                 while (addedTracks != 0) {
                     i = __builtin_ctz(addedTracks);
                     addedTracks &= ~(1 << i);
@@ -312,6 +325,9 @@
                 // finally process modified tracks; these use the same slot
                 // but may have a different buffer provider or volume provider
                 unsigned modifiedTracks = currentTrackMask & previousTrackMask;
+                if (modifiedTracks) {
+                    logWriter->logf("modified %#x", modifiedTracks);
+                }
                 while (modifiedTracks != 0) {
                     i = __builtin_ctz(modifiedTracks);
                     modifiedTracks &= ~(1 << i);
@@ -455,6 +471,7 @@
         struct timespec newTs;
         int rc = clock_gettime(CLOCK_MONOTONIC, &newTs);
         if (rc == 0) {
+            logWriter->logTimestamp(newTs);
             if (oldTsValid) {
                 time_t sec = newTs.tv_sec - oldTs.tv_sec;
                 long nsec = newTs.tv_nsec - oldTs.tv_nsec;
diff --git a/services/audioflinger/FastMixerState.cpp b/services/audioflinger/FastMixerState.cpp
index 6305a83..c45c81b 100644
--- a/services/audioflinger/FastMixerState.cpp
+++ b/services/audioflinger/FastMixerState.cpp
@@ -31,7 +31,7 @@
 FastMixerState::FastMixerState() :
     mFastTracksGen(0), mTrackMask(0), mOutputSink(NULL), mOutputSinkGen(0),
     mFrameCount(0), mCommand(INITIAL), mColdFutexAddr(NULL), mColdGen(0),
-    mDumpState(NULL), mTeeSink(NULL)
+    mDumpState(NULL), mTeeSink(NULL), mNBLogWriter(NULL)
 {
 }
 
diff --git a/services/audioflinger/FastMixerState.h b/services/audioflinger/FastMixerState.h
index 6e53f21..f6e7903 100644
--- a/services/audioflinger/FastMixerState.h
+++ b/services/audioflinger/FastMixerState.h
@@ -20,6 +20,7 @@
 #include <system/audio.h>
 #include <media/ExtendedAudioBufferProvider.h>
 #include <media/nbaio/NBAIO.h>
+#include <media/nbaio/NBLog.h>
 
 namespace android {
 
@@ -77,6 +78,7 @@
     // This might be a one-time configuration rather than per-state
     FastMixerDumpState* mDumpState; // if non-NULL, then update dump state periodically
     NBAIO_Sink* mTeeSink;       // if non-NULL, then duplicate write()s to this non-blocking sink
+    NBLog::Writer* mNBLogWriter; // non-blocking logger
 };  // struct FastMixerState
 
 }   // namespace android
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 744a7df..6f748d7 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -936,6 +936,7 @@
         mFastTrackAvailMask(((1 << FastMixerState::kMaxFastTracks) - 1) & ~1)
 {
     snprintf(mName, kNameLength, "AudioOut_%X", id);
+    mNBLogWriter = audioFlinger->newWriter_l(kLogSize, mName);
 
     // Assumes constructor is called by AudioFlinger with it's mLock held, but
     // it would be safer to explicitly pass initial masterVolume/masterMute as
@@ -971,6 +972,7 @@
 
 AudioFlinger::PlaybackThread::~PlaybackThread()
 {
+    mAudioFlinger->unregisterWriter(mNBLogWriter);
     delete [] mMixBuffer;
 }
 
@@ -1247,6 +1249,7 @@
     if (status) {
         *status = lStatus;
     }
+    mNBLogWriter->logf("createTrack_l");
     return track;
 }
 
@@ -1314,6 +1317,7 @@
 // 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);
     status_t status = ALREADY_EXISTS;
 
     // set retry count for buffer fill
@@ -1347,6 +1351,7 @@
 // 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);
     track->mState = TrackBase::TERMINATED;
     // active tracks are removed by threadLoop()
     if (mActiveTracks.indexOf(track) < 0) {
@@ -1356,6 +1361,7 @@
 
 void AudioFlinger::PlaybackThread::removeTrack_l(const sp<Track>& track)
 {
+    mNBLogWriter->logf("removeTrack_l mName=%d", track->mName);
     track->triggerEvents(AudioSystem::SYNC_EVENT_PRESENTATION_COMPLETE);
     mTracks.remove(track);
     deleteTrackName_l(track->name());
@@ -1892,6 +1898,11 @@
 
     acquireWakeLock();
 
+    // mNBLogWriter->log can only be called while thread mutex mLock is held.
+    // So if you need to log when mutex is unlocked, set logString to a non-NULL string,
+    // and then that string will be logged at the next convenient opportunity.
+    const char *logString = NULL;
+
     while (!exitPending())
     {
         cpuStats.sample(myName);
@@ -1904,6 +1915,12 @@
 
             Mutex::Autolock _l(mLock);
 
+            if (logString != NULL) {
+                mNBLogWriter->logTimestamp();
+                mNBLogWriter->log(logString);
+                logString = NULL;
+            }
+
             if (checkForNewParameters_l()) {
                 cacheParameters_l();
             }
@@ -1917,6 +1934,7 @@
 
                     threadLoop_standby();
 
+                    mNBLogWriter->log("standby");
                     mStandby = true;
                 }
 
@@ -2012,6 +2030,9 @@
         // since we can't guarantee the destructors won't acquire that
         // same lock.  This will also mutate and push a new fast mixer state.
         threadLoop_removeTracks(tracksToRemove);
+        if (tracksToRemove.size() > 0) {
+            logString = "remove";
+        }
         tracksToRemove.clear();
 
         // FIXME I don't understand the need for this here;
@@ -2143,6 +2164,8 @@
         state->mColdGen++;
         state->mDumpState = &mFastMixerDumpState;
         state->mTeeSink = mTeeSink.get();
+        mFastMixerNBLogWriter = audioFlinger->newWriter_l(kFastMixerLogSize, "FastMixer");
+        state->mNBLogWriter = mFastMixerNBLogWriter.get();
         sq->end();
         sq->push(FastMixerStateQueue::BLOCK_UNTIL_PUSHED);
 
@@ -2219,6 +2242,7 @@
         }
 #endif
     }
+    mAudioFlinger->unregisterWriter(mFastMixerNBLogWriter);
     delete mAudioMixer;
 }
 
@@ -2846,6 +2870,7 @@
     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());
             mActiveTracks.remove(track);
             if (track->mainBuffer() != mMixBuffer) {
                 chain = getEffectChain_l(track->sessionId());
@@ -3222,6 +3247,9 @@
     // remove all the tracks that need to be...
     if (CC_UNLIKELY(trackToRemove != 0)) {
         tracksToRemove->add(trackToRemove);
+#if 0
+        mNBLogWriter->logf("prepareTracks_l remove name=%u", trackToRemove->name());
+#endif
         mActiveTracks.remove(trackToRemove);
         if (!mEffectChains.isEmpty()) {
             ALOGV("stopping track on chain %p for session Id: %d", mEffectChains[0].get(),
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 06a1c8c..5fa7eaf 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -315,6 +315,8 @@
                 // keyed by session ID, the second by type UUID timeLow field
                 KeyedVector< int, KeyedVector< int, sp<SuspendedSessionDesc> > >
                                         mSuspendedSessions;
+                static const size_t     kLogSize = 512;
+                sp<NBLog::Writer>       mNBLogWriter;
 };
 
 // --- PlaybackThread ---
@@ -544,6 +546,8 @@
     sp<NBAIO_Sink>          mTeeSink;
     sp<NBAIO_Source>        mTeeSource;
     uint32_t                mScreenState;   // cached copy of gScreenState
+    static const size_t     kFastMixerLogSize = 8 * 1024;
+    sp<NBLog::Writer>       mFastMixerNBLogWriter;
 public:
     virtual     bool        hasFastMixer() const = 0;
     virtual     FastTrackUnderruns getFastTrackUnderruns(size_t fastIndex) const
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index c5f0ed7..315cbbc 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -569,6 +569,7 @@
     sp<ThreadBase> thread = mThread.promote();
     if (thread != 0) {
         Mutex::Autolock _l(thread->mLock);
+        thread->mNBLogWriter->logf("start mName=%d", mName);
         track_state state = mState;
         // here the track could be either new, or restarted
         // in both cases "unstop" the track
@@ -611,6 +612,7 @@
     sp<ThreadBase> thread = mThread.promote();
     if (thread != 0) {
         Mutex::Autolock _l(thread->mLock);
+        thread->mNBLogWriter->logf("stop mName=%d", mName);
         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
@@ -647,6 +649,7 @@
     sp<ThreadBase> thread = mThread.promote();
     if (thread != 0) {
         Mutex::Autolock _l(thread->mLock);
+        thread->mNBLogWriter->logf("pause mName=%d", mName);
         if (mState == ACTIVE || mState == RESUMING) {
             mState = PAUSING;
             ALOGV("ACTIVE/RESUMING => PAUSING (%d) on thread %p", mName, thread.get());
@@ -670,6 +673,7 @@
     sp<ThreadBase> thread = mThread.promote();
     if (thread != 0) {
         Mutex::Autolock _l(thread->mLock);
+        thread->mNBLogWriter->logf("flush mName=%d", mName);
         if (mState != STOPPING_1 && mState != STOPPING_2 && mState != STOPPED && mState != PAUSED &&
                 mState != PAUSING && mState != IDLE && mState != FLUSHED) {
             return;
diff --git a/services/medialog/Android.mk b/services/medialog/Android.mk
new file mode 100644
index 0000000..559b1ed
--- /dev/null
+++ b/services/medialog/Android.mk
@@ -0,0 +1,11 @@
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := MediaLogService.cpp
+
+LOCAL_SHARED_LIBRARIES := libmedia libbinder libutils libnbaio
+
+LOCAL_MODULE:= libmedialogservice
+
+include $(BUILD_SHARED_LIBRARY)
diff --git a/services/medialog/MediaLogService.cpp b/services/medialog/MediaLogService.cpp
new file mode 100644
index 0000000..2332b3e
--- /dev/null
+++ b/services/medialog/MediaLogService.cpp
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "MediaLog"
+//#define LOG_NDEBUG 0
+
+#include <sys/mman.h>
+#include <utils/Log.h>
+#include <media/nbaio/NBLog.h>
+#include <private/android_filesystem_config.h>
+#include "MediaLogService.h"
+
+namespace android {
+
+void MediaLogService::registerWriter(const sp<IMemory>& shared, size_t size, const char *name)
+{
+    if (IPCThreadState::self()->getCallingUid() != AID_MEDIA || shared == 0 ||
+            size < kMinSize || size > kMaxSize || name == NULL ||
+            shared->size() < NBLog::Timeline::sharedSize(size)) {
+        return;
+    }
+    sp<NBLog::Reader> reader(new NBLog::Reader(size, shared));
+    NamedReader namedReader(reader, name);
+    Mutex::Autolock _l(mLock);
+    mNamedReaders.add(namedReader);
+}
+
+void MediaLogService::unregisterWriter(const sp<IMemory>& shared)
+{
+    if (IPCThreadState::self()->getCallingUid() != AID_MEDIA || shared == 0) {
+        return;
+    }
+    Mutex::Autolock _l(mLock);
+    for (size_t i = 0; i < mNamedReaders.size(); ) {
+        if (mNamedReaders[i].reader()->isIMemory(shared)) {
+            mNamedReaders.removeAt(i);
+        } else {
+            i++;
+        }
+    }
+}
+
+status_t MediaLogService::dump(int fd, const Vector<String16>& args)
+{
+    Vector<NamedReader> namedReaders;
+    {
+        Mutex::Autolock _l(mLock);
+        namedReaders = mNamedReaders;
+    }
+    for (size_t i = 0; i < namedReaders.size(); i++) {
+        const NamedReader& namedReader = namedReaders[i];
+        if (fd >= 0) {
+            fdprintf(fd, "\n%s:\n", namedReader.name());
+        } else {
+            ALOGI("%s:", namedReader.name());
+        }
+        namedReader.reader()->dump(fd, 0 /*indent*/);
+    }
+    return NO_ERROR;
+}
+
+status_t MediaLogService::onTransact(uint32_t code, const Parcel& data, Parcel* reply,
+        uint32_t flags)
+{
+    return BnMediaLogService::onTransact(code, data, reply, flags);
+}
+
+}   // namespace android
diff --git a/services/medialog/MediaLogService.h b/services/medialog/MediaLogService.h
new file mode 100644
index 0000000..2d89a41
--- /dev/null
+++ b/services/medialog/MediaLogService.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_MEDIA_LOG_SERVICE_H
+#define ANDROID_MEDIA_LOG_SERVICE_H
+
+#include <binder/BinderService.h>
+#include <media/IMediaLogService.h>
+#include <media/nbaio/NBLog.h>
+
+namespace android {
+
+class MediaLogService : public BinderService<MediaLogService>, public BnMediaLogService
+{
+    friend class BinderService<MediaLogService>;    // for MediaLogService()
+public:
+    MediaLogService() : BnMediaLogService() { }
+    virtual ~MediaLogService() { }
+    virtual void onFirstRef() { }
+
+    static const char*  getServiceName() { return "media.log"; }
+
+    static const size_t kMinSize = 0x100;
+    static const size_t kMaxSize = 0x10000;
+    virtual void        registerWriter(const sp<IMemory>& shared, size_t size, const char *name);
+    virtual void        unregisterWriter(const sp<IMemory>& shared);
+
+    virtual status_t    dump(int fd, const Vector<String16>& args);
+    virtual status_t    onTransact(uint32_t code, const Parcel& data, Parcel* reply,
+                                uint32_t flags);
+
+private:
+    Mutex               mLock;
+    class NamedReader {
+    public:
+        NamedReader() : mReader(0) { mName[0] = '\0'; } // for Vector
+        NamedReader(const sp<NBLog::Reader>& reader, const char *name) : mReader(reader)
+            { strlcpy(mName, name, sizeof(mName)); }
+        ~NamedReader() { }
+        const sp<NBLog::Reader>&  reader() const { return mReader; }
+        const char*               name() const { return mName; }
+    private:
+        sp<NBLog::Reader>   mReader;
+        static const size_t kMaxName = 32;
+        char                mName[kMaxName];
+    };
+    Vector<NamedReader> mNamedReaders;
+};
+
+}   // namespace android
+
+#endif  // ANDROID_MEDIA_LOG_SERVICE_H