From 019959a0124cad79efd2260a1c8c945c8c10f657 Mon Sep 17 00:00:00 2001
From: Themaister <maister@archlinux.us>
Date: Fri, 18 Jan 2013 10:38:43 +0100
Subject: [PATCH 1/2] Add audio buffer statistics measurement.

---
 driver.c    | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 general.h   |  4 ++++
 retroarch.c |  3 +++
 3 files changed, 55 insertions(+)

diff --git a/driver.c b/driver.c
index 6f1a387b87..28a360c2cf 100644
--- a/driver.c
+++ b/driver.c
@@ -434,6 +434,52 @@ void init_audio(void)
 #ifdef HAVE_DYLIB
    init_dsp_plugin();
 #endif
+
+   g_extern.audio_data.buffer_free_samples_count = 0;
+}
+
+static void compute_audio_buffer_statistics(void)
+{
+   unsigned samples = min(g_extern.audio_data.buffer_free_samples_count, AUDIO_BUFFER_FREE_SAMPLES_COUNT);
+   if (!samples)
+      return;
+
+   uint64_t accum = 0;
+   for (unsigned i = 0; i < samples; i++)
+      accum += g_extern.audio_data.buffer_free_samples[i];
+
+   int avg = accum / samples;
+
+   uint64_t accum_var = 0;
+   for (unsigned i = 0; i < samples; i++)
+   {
+      int diff = avg - g_extern.audio_data.buffer_free_samples[i];
+      accum_var += diff * diff;
+   }
+
+   unsigned stddev = (unsigned)sqrtf((float)accum_var / samples);
+
+   float avg_filled = 1.0f - (float)avg / g_extern.audio_data.driver_buffer_size;
+   float deviation = (float)stddev / g_extern.audio_data.driver_buffer_size;
+
+   unsigned low_water_size = g_extern.audio_data.driver_buffer_size * 3 / 4;
+   unsigned high_water_size = g_extern.audio_data.driver_buffer_size / 4;
+
+   unsigned low_water_count = 0;
+   unsigned high_water_count = 0;
+   for (unsigned i = 0; i < samples; i++)
+   {
+      if (g_extern.audio_data.buffer_free_samples[i] >= low_water_size)
+         low_water_count++;
+      else if (g_extern.audio_data.buffer_free_samples[i] <= high_water_size)
+         high_water_count++;
+   }
+
+   RARCH_LOG("Average audio buffer saturation: %.2f %%, standard deviation (percentage points): %.2f %%.\n",
+         avg_filled * 100.0, deviation * 100.0);
+   RARCH_LOG("Amount of time spent close to underrun: %.2f %%. Close to blocking: %.2f %%.\n",
+         (100.0 * low_water_count) / samples,
+         (100.0 * high_water_count) / samples);
 }
 
 void uninit_audio(void)
@@ -466,6 +512,8 @@ void uninit_audio(void)
 #ifdef HAVE_DYLIB
    deinit_dsp_plugin();
 #endif
+
+   compute_audio_buffer_statistics();
 }
 
 #ifdef HAVE_DYLIB
diff --git a/general.h b/general.h
index d456a76592..38275bb9c3 100644
--- a/general.h
+++ b/general.h
@@ -401,6 +401,10 @@ struct global
 
       float volume_db;
       float volume_gain;
+
+#define AUDIO_BUFFER_FREE_SAMPLES_COUNT (8 * 1024)
+      unsigned buffer_free_samples[AUDIO_BUFFER_FREE_SAMPLES_COUNT];
+      uint64_t buffer_free_samples_count;
    } audio_data;
 
    struct
diff --git a/retroarch.c b/retroarch.c
index f1c40397fa..fbf78512b8 100644
--- a/retroarch.c
+++ b/retroarch.c
@@ -182,6 +182,9 @@ static void readjust_audio_input_rate(void)
    //RARCH_LOG_OUTPUT("Audio buffer is %u%% full\n",
    //      (unsigned)(100 - (avail * 100) / g_extern.audio_data.driver_buffer_size));
 
+   unsigned write_index = (g_extern.audio_data.buffer_free_samples_count++) & (AUDIO_BUFFER_FREE_SAMPLES_COUNT - 1);
+   g_extern.audio_data.buffer_free_samples[write_index] = avail;
+
    int half_size = g_extern.audio_data.driver_buffer_size / 2;
    int delta_mid = avail - half_size;
    double direction = (double)delta_mid / half_size;

From b7b569d4eaf26f79dd22c71e4a17919874a209bb Mon Sep 17 00:00:00 2001
From: Themaister <maister@archlinux.us>
Date: Fri, 18 Jan 2013 11:14:38 +0100
Subject: [PATCH 2/2] Actually use POT size in SL.

---
 audio/opensl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/audio/opensl.c b/audio/opensl.c
index 4be267542e..c2ab6bea2a 100644
--- a/audio/opensl.c
+++ b/audio/opensl.c
@@ -34,7 +34,7 @@
 #define SLPlayItf_SetPlayState(a, ...) ((*(a))->SetPlayState(a, __VA_ARGS__))
 
 // TODO: Are these sane?
-#define BUFFER_SIZE 8092
+#define BUFFER_SIZE 8192
 #define BUFFER_COUNT 4
 
 typedef struct sl