ALSA: pcm_lib - optimize wake_up() calls for PCM I/O
As noted by pl bossart <bossart.nospam@gmail.com>, the PCM I/O routines
(snd_pcm_lib_write1, snd_pcm_lib_read1) should block wake_up() calls
until all samples are not processed.
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index fe1b131..e26fb3c 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -311,6 +311,7 @@
struct snd_pcm_mmap_control *control;
/* -- locking / scheduling -- */
+ unsigned int nowake: 1; /* no wakeup (data-copy in progress) */
wait_queue_head_t sleep;
struct fasync_struct *fasync;
@@ -839,6 +840,8 @@
int snd_pcm_lib_interleave_len(struct snd_pcm_substream *substream);
int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream,
unsigned int cmd, void *arg);
+int snd_pcm_update_state(struct snd_pcm_substream *substream,
+ struct snd_pcm_runtime *runtime);
int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream);
int snd_pcm_playback_xrun_check(struct snd_pcm_substream *substream);
int snd_pcm_capture_xrun_check(struct snd_pcm_substream *substream);
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 70a4f74..a632262 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -263,8 +263,8 @@
#endif
-static int snd_pcm_update_hw_ptr_post(struct snd_pcm_substream *substream,
- struct snd_pcm_runtime *runtime)
+int snd_pcm_update_state(struct snd_pcm_substream *substream,
+ struct snd_pcm_runtime *runtime)
{
snd_pcm_uframes_t avail;
@@ -285,7 +285,7 @@
return -EPIPE;
}
}
- if (avail >= runtime->control->avail_min)
+ if (!runtime->nowake && avail >= runtime->control->avail_min)
wake_up(&runtime->sleep);
return 0;
}
@@ -441,7 +441,7 @@
if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE)
snd_pcm_gettime(runtime, (struct timespec *)&runtime->status->tstamp);
- return snd_pcm_update_hw_ptr_post(substream, runtime);
+ return snd_pcm_update_state(substream, runtime);
}
/* CAUTION: call it with irq disabled */
@@ -1792,6 +1792,7 @@
goto _end_unlock;
}
+ runtime->nowake = 1;
while (size > 0) {
snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
snd_pcm_uframes_t avail;
@@ -1813,15 +1814,17 @@
if (frames > cont)
frames = cont;
if (snd_BUG_ON(!frames)) {
+ runtime->nowake = 0;
snd_pcm_stream_unlock_irq(substream);
return -EINVAL;
}
appl_ptr = runtime->control->appl_ptr;
appl_ofs = appl_ptr % runtime->buffer_size;
snd_pcm_stream_unlock_irq(substream);
- if ((err = transfer(substream, appl_ofs, data, offset, frames)) < 0)
- goto _end;
+ err = transfer(substream, appl_ofs, data, offset, frames);
snd_pcm_stream_lock_irq(substream);
+ if (err < 0)
+ goto _end_unlock;
switch (runtime->status->state) {
case SNDRV_PCM_STATE_XRUN:
err = -EPIPE;
@@ -1850,8 +1853,10 @@
}
}
_end_unlock:
+ runtime->nowake = 0;
+ if (xfer > 0 && err >= 0)
+ snd_pcm_update_state(substream, runtime);
snd_pcm_stream_unlock_irq(substream);
- _end:
return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}
@@ -2009,6 +2014,7 @@
goto _end_unlock;
}
+ runtime->nowake = 1;
while (size > 0) {
snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
snd_pcm_uframes_t avail;
@@ -2037,15 +2043,17 @@
if (frames > cont)
frames = cont;
if (snd_BUG_ON(!frames)) {
+ runtime->nowake = 0;
snd_pcm_stream_unlock_irq(substream);
return -EINVAL;
}
appl_ptr = runtime->control->appl_ptr;
appl_ofs = appl_ptr % runtime->buffer_size;
snd_pcm_stream_unlock_irq(substream);
- if ((err = transfer(substream, appl_ofs, data, offset, frames)) < 0)
- goto _end;
+ err = transfer(substream, appl_ofs, data, offset, frames);
snd_pcm_stream_lock_irq(substream);
+ if (err < 0)
+ goto _end_unlock;
switch (runtime->status->state) {
case SNDRV_PCM_STATE_XRUN:
err = -EPIPE;
@@ -2068,8 +2076,10 @@
xfer += frames;
}
_end_unlock:
+ runtime->nowake = 0;
+ if (xfer > 0 && err >= 0)
+ snd_pcm_update_state(substream, runtime);
snd_pcm_stream_unlock_irq(substream);
- _end:
return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 8e777f7..27284f6 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -516,6 +516,7 @@
struct snd_pcm_sw_params *params)
{
struct snd_pcm_runtime *runtime;
+ int err;
if (PCM_RUNTIME_CHECK(substream))
return -ENXIO;
@@ -540,6 +541,7 @@
if (params->silence_threshold > runtime->buffer_size)
return -EINVAL;
}
+ err = 0;
snd_pcm_stream_lock_irq(substream);
runtime->tstamp_mode = params->tstamp_mode;
runtime->period_step = params->period_step;
@@ -553,10 +555,10 @@
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
runtime->silence_size > 0)
snd_pcm_playback_silence(substream, ULONG_MAX);
- wake_up(&runtime->sleep);
+ err = snd_pcm_update_state(substream, runtime);
}
snd_pcm_stream_unlock_irq(substream);
- return 0;
+ return err;
}
static int snd_pcm_sw_params_user(struct snd_pcm_substream *substream,