don't busy wait for the decoder thread

Busy wait loops are a bad thing, especially when the response time can be very long - busy waits eat a lot of CPU, and thus slow down the other thread. Since the other thread will notify us when it's ready, we can use notify_wait() instead.

don't busy wait for the decoder thread
726c6e86 · Max Kellermann · 8d3942e0 · 726c6e86
Commit 726c6e86 authored Aug 26, 2008 by Max Kellermann
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Showing with 7 additions and 3 deletions

decode.c src/decode.c +7 -3

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--- a/src/decode.c
+++ b/src/decode.c
@@ -58,8 +58,10 @@ static void player_wakeup_decoder(void)

 static void dc_command_wait(void)
 {
-	while (dc.command != DECODE_COMMAND_NONE)
+	while (dc.command != DECODE_COMMAND_NONE) {
 		player_wakeup_decoder_nb();
+		notify_wait(&pc.notify);
+	}
 }

 static void dc_command(enum decoder_command cmd)
@@ -112,8 +114,10 @@ static unsigned calculateCrossFadeChunks(AudioFormat * af, float totalTime)

 static int waitOnDecode(int *decodeWaitedOn)
 {
-	while (dc.command == DECODE_COMMAND_START)
-		player_wakeup_decoder();
+	while (dc.command == DECODE_COMMAND_START) {
+		notify_signal(&dc.notify);
+		notify_wait(&pc.notify);
+	}

 	if (dc.error != DECODE_ERROR_NOERROR) {
 		pc.errored_song = dc.next_song;