ALSA: pcm: optimize xrun detection in no-period-wakeup mode
Add a lightweight condition on top of the xrun checking so that we can
avoid the division when the application is calling the update function
often enough.
Suggested-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index e9debaa..fd18c3c 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -380,6 +380,8 @@
* the elapsed time to detect xruns.
*/
jdelta = jiffies - runtime->hw_ptr_jiffies;
+ if (jdelta < runtime->hw_ptr_buffer_jiffies / 2)
+ goto no_delta_check;
hdelta = jdelta - delta * HZ / runtime->rate;
while (hdelta > runtime->hw_ptr_buffer_jiffies / 2 + 1) {
delta += runtime->buffer_size;