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>

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>
Clemens Ladisch · Takashi Iwai
1 parent 59ff878ffb
Showing 1 changed file with 2 additions and 0 deletions Side-by-side Diff
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;
...	...	@@ -380,6 +380,8 @@
380	380	* the elapsed time to detect xruns.
381	381	*/
382	382	jdelta = jiffies - runtime->hw_ptr_jiffies;
	383	+ if (jdelta < runtime->hw_ptr_buffer_jiffies / 2)
	384	+ goto no_delta_check;
383	385	hdelta = jdelta - delta * HZ / runtime->rate;
384	386	while (hdelta > runtime->hw_ptr_buffer_jiffies / 2 + 1) {
385	387	delta += runtime->buffer_size;