alsaloop: try adapt avail_min for playback to avoid 100% CPU usage

diff --git a/alsaloop/alsaloop.h b/alsaloop/alsaloop.h
index 8dc445ae2fc69315d7f8f29d9ef9682756a6b7a1..71eab20d540a8185dd22ee7d846f17d960cf7c41 100644 (file)
--- a/alsaloop/alsaloop.h
+++ b/alsaloop/alsaloop.h
@@ -109,6 +109,7 @@ struct loopback_handle {
        snd_pcm_uframes_t buf_count;    /* filled samples */
        snd_pcm_uframes_t buf_size;     /* buffer size in frames */
        snd_pcm_uframes_t buf_over;     /* capture buffer overflow */
+       int stall;
        /* statistics */
        snd_pcm_uframes_t max;
        unsigned long long counter;

diff --git a/alsaloop/pcmjob.c b/alsaloop/pcmjob.c
index f32180c8e8cdeb6b36ab869cfb93fa3c1d2514b2..4df59e86c1f85a54b898f4e0bb57deed952eb2a2 100644 (file)
--- a/alsaloop/pcmjob.c
+++ b/alsaloop/pcmjob.c
@@ -282,6 +282,35 @@ static int setparams_set(struct loopback_handle *lhandle,
        return 0;
 }
 
+static int increase_playback_avail_min(struct loopback_handle *lhandle)
+{
+       snd_pcm_t *handle = lhandle->handle;
+       snd_pcm_sw_params_t *swparams;
+       int err;
+
+       snd_pcm_sw_params_alloca(&swparams);
+       err = snd_pcm_sw_params_current(handle, swparams);
+       if (err < 0) {
+               logit(LOG_CRIT, "Unable to determine current swparams for %s: %s\n", lhandle->id, snd_strerror(err));
+               return err;
+       }
+       err = snd_pcm_sw_params_set_avail_min(handle, swparams, lhandle->avail_min + 4);
+       if (err < 0) {
+               logit(LOG_CRIT, "Unable to set avail min for %s: %s\n", lhandle->id, snd_strerror(err));
+               return err;
+       }
+       snd_pcm_sw_params_get_avail_min(swparams, &lhandle->avail_min);
+       if (verbose > 6)
+               snd_output_printf(lhandle->loopback->output, "%s: change avail_min=%li\n", lhandle->id, lhandle->avail_min);
+       printf("%s: change avail_min=%li\n", lhandle->id, lhandle->avail_min);
+       err = snd_pcm_sw_params(handle, swparams);
+       if (err < 0) {
+               logit(LOG_CRIT, "Unable to set sw params for %s: %s\n", lhandle->id, snd_strerror(err));
+               return err;
+       }
+       return 0;
+}
+
 static int setparams(struct loopback *loop, snd_pcm_uframes_t bufsize)
 {
        int err;
@@ -1763,7 +1792,7 @@ int pcmjob_pollfds_handle(struct loopback *loop, struct pollfd *fds)
        struct loopback_handle *capt = loop->capt;
        unsigned short prevents, crevents, events;
        snd_pcm_uframes_t ccount, pcount;
-       int err, loopcount = 10, idx;
+       int err, loopcount = 0, idx;
 
        if (verbose > 11)
                snd_output_printf(loop->output, "%s: pollfds handle\n", loop->id);
@@ -1843,6 +1872,18 @@ int pcmjob_pollfds_handle(struct loopback *loop, struct pollfd *fds)
                goto __pcm_end;
        do {
                ccount = readit(capt);
+               if (prevents != 0 && crevents == 0 &&
+                   ccount == 0 && loopcount == 0) {
+                       if (play->stall > 20) {
+                               play->stall = 0;
+                               increase_playback_avail_min(play);
+                               break;
+                       }
+                       play->stall++;
+                       break;
+               }
+               if (ccount > 0)
+                       play->stall = 0;
                buf_add(loop, ccount);
                if (capt->xrun_pending || loop->reinit)
                        break;
@@ -1850,10 +1891,12 @@ int pcmjob_pollfds_handle(struct loopback *loop, struct pollfd *fds)
                   buffer, feed them there */
                pcount = writeit(play);
                buf_remove(loop, pcount);
+               if (pcount > 0)
+                       play->stall = 0;
                if (play->xrun_pending || loop->reinit)
                        break;
-               loopcount--;
-       } while ((ccount > 0 || pcount > 0) && loopcount > 0);
+               loopcount++;
+       } while ((ccount > 0 || pcount > 0) && loopcount > 10);
        if (play->xrun_pending || capt->xrun_pending) {
                if ((err = xrun_sync(loop)) < 0)
                        return err;