From a85044bf9eaa0a7206c1978d3cfd57ab2d7fae2f Mon Sep 17 00:00:00 2001
From: Miika Pekkarinen <miipekk@ihme.org>
Date: Sat, 16 Sep 2006 16:18:11 +0000
Subject: New scheduler, with priorities for swcodec platforms. Frequent task
 switching should be more efficient and tasks are stored in linked lists to
 eliminate unnecessary task switching to improve performance. Audio should no
 longer skip on swcodec targets caused by too CPU hungry UI thread or
 background threads.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@10958 a1c6a512-1295-4272-9138-f99709370657
---
 apps/pcmbuf.c | 42 +++++++++++++++++++++++++++++++++++-------
 1 file changed, 35 insertions(+), 7 deletions(-)

(limited to 'apps/pcmbuf.c')

diff --git a/apps/pcmbuf.c b/apps/pcmbuf.c
index b18d411db6..f8fd2af82a 100644
--- a/apps/pcmbuf.c
+++ b/apps/pcmbuf.c
@@ -35,9 +35,10 @@
 #include "settings.h"
 #include "audio.h"
 #include "dsp.h"
+#include "thread.h"
 
-/* 1.5s low mark */
-#define PCMBUF_WATERMARK     (NATIVE_FREQUENCY * 6)
+/* Keep watermark high for iPods at least (2s) */
+#define PCMBUF_WATERMARK     (NATIVE_FREQUENCY * 8)
 
 /* Structure we can use to queue pcm chunks in memory to be played
  * by the driver code. */
@@ -94,6 +95,8 @@ static size_t pcmbuf_mix_sample IDATA_ATTR;
 static bool low_latency_mode = false;
 static bool pcmbuf_flush;
 
+extern struct thread_entry *codec_thread_p;
+
 /* Helpful macros for use in conditionals this assumes some of the above
  * static variable names */
 #define NEED_FLUSH(position) \
@@ -109,14 +112,37 @@ static bool pcmbuf_flush_fillpos(void);
 void pcmbuf_boost(bool state)
 {
     static bool boost_state = false;
-
+#ifdef HAVE_PRIORITY_SCHEDULING
+    static bool priority_modified = false;
+#endif
+    
     if (crossfade_init || crossfade_active)
         return;
 
-    if (state != boost_state) {
+    if (state != boost_state)
+    {
         cpu_boost(state);
         boost_state = state;
     }
+    
+#ifdef HAVE_PRIORITY_SCHEDULING
+    if (state && LOW_DATA(2) && pcm_is_playing())
+    {
+        if (!priority_modified)
+        {
+            /* Buffer is critically low so override UI priority. */
+            priority_modified = true;
+            thread_set_priority(codec_thread_p, PRIORITY_REALTIME);
+        }
+    }
+    else if (priority_modified)
+    {
+        /* Set back the original priority. */
+        thread_set_priority(codec_thread_p, PRIORITY_PLAYBACK);
+        priority_modified = false;
+    }
+    
+#endif
 }
 #endif
 
@@ -244,7 +270,9 @@ static void pcmbuf_under_watermark(void)
     pcmbuf_boost(true);
     /* Disable crossfade if < .5s of audio */
     if (LOW_DATA(2))
+    {
         crossfade_active = false;
+    }
 }
 
 void pcmbuf_set_event_handler(void (*event_handler)(void))
@@ -270,8 +298,8 @@ bool pcmbuf_is_lowdata(void)
             crossfade_init || crossfade_active)
         return false;
 
-    /* 0.5 seconds of buffer is low data */
-    return LOW_DATA(2);
+    /* 1 seconds of buffer is low data */
+    return LOW_DATA(4);
 }
 
 /* Amount of bytes left in the buffer. */
@@ -443,7 +471,7 @@ static bool pcmbuf_flush_fillpos(void)
                 pcmbuf_play_start();
             }
             /* Let approximately one chunk of data playback */
-            sleep(PCMBUF_TARGET_CHUNK/(NATIVE_FREQUENCY * 4) / 5);
+            sleep(HZ*PCMBUF_TARGET_CHUNK/(NATIVE_FREQUENCY*4));
         }
         pcmbuf_add_chunk();
         return true;
-- 
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