diff --git a/media/libaaudio/src/client/IsochronousClockModel.cpp b/media/libaaudio/src/client/IsochronousClockModel.cpp
index 07b6ad0..bd46d05 100644
--- a/media/libaaudio/src/client/IsochronousClockModel.cpp
+++ b/media/libaaudio/src/client/IsochronousClockModel.cpp
@@ -18,18 +18,30 @@
 //#define LOG_NDEBUG 0
 #include <log/log.h>
 
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
 #include <stdint.h>
 #include <algorithm>
 
 #include "utility/AudioClock.h"
+#include "utility/AAudioUtilities.h"
 #include "IsochronousClockModel.h"
 
 using namespace aaudio;
 
+using namespace android::audio_utils;
+
 #ifndef ICM_LOG_DRIFT
 #define ICM_LOG_DRIFT   0
 #endif // ICM_LOG_DRIFT
 
+// To enable the timestamp histogram, enter this before opening the stream:
+//    adb root
+//    adb shell setprop aaudio.log_mask 1
+// A histogram of the lateness of the timestamps will be cleared when the stream is started.
+// It will be updated when the model is stable and receives a timestamp,
+// and dumped to the log when the stream is stopped.
+
 IsochronousClockModel::IsochronousClockModel()
         : mMarkerFramePosition(0)
         , mMarkerNanoTime(0)
@@ -39,6 +51,10 @@
         , mLatenessForDriftNanos(kInitialLatenessForDriftNanos)
         , mState(STATE_STOPPED)
 {
+    if ((AAudioProperty_getLogMask() & AAUDIO_LOG_CLOCK_MODEL_HISTOGRAM) != 0) {
+        mHistogramMicros = std::make_unique<Histogram>(kHistogramBinCount,
+                kHistogramBinWidthMicros);
+    }
 }
 
 IsochronousClockModel::~IsochronousClockModel() {
@@ -54,6 +70,9 @@
     ALOGV("start(nanos = %lld)\n", (long long) nanoTime);
     mMarkerNanoTime = nanoTime;
     mState = STATE_STARTING;
+    if (mHistogramMicros) {
+        mHistogramMicros->clear();
+    }
 }
 
 void IsochronousClockModel::stop(int64_t nanoTime) {
@@ -63,6 +82,9 @@
     setPositionAndTime(convertTimeToPosition(nanoTime), nanoTime);
     // TODO should we set position?
     mState = STATE_STOPPED;
+    if (mHistogramMicros) {
+        dumpHistogram();
+    }
 }
 
 bool IsochronousClockModel::isStarting() const {
@@ -113,6 +135,9 @@
         }
         break;
     case STATE_RUNNING:
+        if (mHistogramMicros) {
+            mHistogramMicros->add(latenessNanos / AAUDIO_NANOS_PER_MICROSECOND);
+        }
         // Modify estimated position based on lateness.
         // This affects the "early" side of the window, which controls output glitches.
         if (latenessNanos < 0) {
@@ -121,10 +146,9 @@
             // Or we may be drifting due to a fast HW clock.
             setPositionAndTime(framePosition, nanoTime);
 #if ICM_LOG_DRIFT
-            int microsDelta = (int) (nanosDelta / 1000);
-            int expectedMicrosDelta = (int) (expectedNanosDelta / 1000);
+            int earlyDeltaMicros = (int) ((expectedNanosDelta - nanosDelta)/ 1000);
             ALOGD("%s() - STATE_RUNNING - #%d, %4d micros EARLY",
-                __func__, mTimestampCount, expectedMicrosDelta - microsDelta);
+                __func__, mTimestampCount, earlyDeltaMicros);
 #endif
         } else if (latenessNanos > mLatenessForDriftNanos) {
             // When we are on the late side, it may be because of preemption in the kernel,
@@ -242,10 +266,19 @@
 }
 
 void IsochronousClockModel::dump() const {
-    ALOGD("mMarkerFramePosition = %16lld", (long long) mMarkerFramePosition);
-    ALOGD("mMarkerNanoTime      = %16lld", (long long) mMarkerNanoTime);
-    ALOGD("mSampleRate          = %8d", mSampleRate);
-    ALOGD("mFramesPerBurst      = %8d", mFramesPerBurst);
-    ALOGD("mState               = %8d", mState);
-    ALOGD("max lateness nanos   = %8d", mMaxMeasuredLatenessNanos);
+    ALOGD("mMarkerFramePosition = %" PRIu64, mMarkerFramePosition);
+    ALOGD("mMarkerNanoTime      = %" PRIu64, mMarkerNanoTime);
+    ALOGD("mSampleRate          = %6d", mSampleRate);
+    ALOGD("mFramesPerBurst      = %6d", mFramesPerBurst);
+    ALOGD("mMaxMeasuredLatenessNanos = %6d", mMaxMeasuredLatenessNanos);
+    ALOGD("mState               = %6d", mState);
+}
+
+void IsochronousClockModel::dumpHistogram() const {
+    if (!mHistogramMicros) return;
+    std::istringstream istr(mHistogramMicros->dump());
+    std::string line;
+    while (std::getline(istr, line)) {
+        ALOGD("lateness, %s", line.c_str());
+    }
 }
diff --git a/media/libaaudio/src/client/IsochronousClockModel.h b/media/libaaudio/src/client/IsochronousClockModel.h
index a86d264..40f066b 100644
--- a/media/libaaudio/src/client/IsochronousClockModel.h
+++ b/media/libaaudio/src/client/IsochronousClockModel.h
@@ -18,6 +18,9 @@
 #define ANDROID_AAUDIO_ISOCHRONOUS_CLOCK_MODEL_H
 
 #include <stdint.h>
+
+#include <audio_utils/Histogram.h>
+
 #include "utility/AudioClock.h"
 
 namespace aaudio {
@@ -122,6 +125,8 @@
 
     void dump() const;
 
+    void dumpHistogram() const;
+
 private:
 
     int32_t getLateTimeOffsetNanos() const;
@@ -140,6 +145,9 @@
     // Initial small threshold for causing a drift later in time.
     static constexpr int32_t   kInitialLatenessForDriftNanos = 10 * 1000;
 
+    static constexpr int32_t   kHistogramBinWidthMicros = 50;
+    static constexpr int32_t   kHistogramBinCount = 128;
+
     int64_t             mMarkerFramePosition; // Estimated HW position.
     int64_t             mMarkerNanoTime;      // Estimated HW time.
     int32_t             mSampleRate;
@@ -153,6 +161,9 @@
 
     int32_t             mTimestampCount = 0;  // For logging.
 
+    // distribution of timestamps relative to earliest
+    std::unique_ptr<android::audio_utils::Histogram>   mHistogramMicros;
+
     void update();
 };
 
diff --git a/media/libaaudio/src/utility/AAudioUtilities.cpp b/media/libaaudio/src/utility/AAudioUtilities.cpp
index 0ff6333..c2f7fd0 100644
--- a/media/libaaudio/src/utility/AAudioUtilities.cpp
+++ b/media/libaaudio/src/utility/AAudioUtilities.cpp
@@ -359,6 +359,10 @@
     return AAudioProperty_getMMapOffsetMicros(__func__, AAUDIO_PROP_OUTPUT_MMAP_OFFSET_USEC);
 }
 
+int32_t AAudioProperty_getLogMask() {
+    return property_get_int32(AAUDIO_PROP_LOG_MASK, 0);
+}
+
 aaudio_result_t AAudio_isFlushAllowed(aaudio_stream_state_t state) {
     aaudio_result_t result = AAUDIO_OK;
     switch (state) {
diff --git a/media/libaaudio/src/utility/AAudioUtilities.h b/media/libaaudio/src/utility/AAudioUtilities.h
index 55824f7..5dcddf3 100644
--- a/media/libaaudio/src/utility/AAudioUtilities.h
+++ b/media/libaaudio/src/utility/AAudioUtilities.h
@@ -162,6 +162,20 @@
 int32_t AAudioProperty_getOutputMMapOffsetMicros();
 #define AAUDIO_PROP_OUTPUT_MMAP_OFFSET_USEC   "aaudio.out_mmap_offset_usec"
 
+// These are powers of two that can be combined as a bit mask.
+// AAUDIO_LOG_CLOCK_MODEL_HISTOGRAM must be enabled before the stream is opened.
+#define AAUDIO_LOG_CLOCK_MODEL_HISTOGRAM   1
+#define AAUDIO_LOG_RESERVED_2              2
+#define AAUDIO_LOG_RESERVED_4              4
+#define AAUDIO_LOG_RESERVED_8              8
+
+/**
+ * Use a mask to enable various logs in AAudio.
+ * @return mask that enables various AAudio logs, such as AAUDIO_LOG_CLOCK_MODEL_HISTOGRAM
+ */
+int32_t AAudioProperty_getLogMask();
+#define AAUDIO_PROP_LOG_MASK   "aaudio.log_mask"
+
 /**
  * Is flush allowed for the given state?
  * @param state