Debian Bug report logs - #613203
audacious: High CPU usage with snd_hda_intel based soundcard

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: "Fabien C." <nsvoaiwvs9bmebb@jetable.org>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: audacious: High CPU usage with snd_hda_intel based soundcard

Date: Sun, 13 Feb 2011 15:01:04 +0100

Package: audacious
Version: 2.3-2
Severity: important
Tags: upstream

CPU Usage is too high when playing audio files. Considering old bug reports and various internet sources, it seems to occur particularly with Intel HDA (snd_hda_intel) soundcards, the model I have on this box. 
On Intel Core2 CPU with "ondemand" governor (lowest freq.: 800Mhz) audacious consumes about 12 to 35-40% of CPU according to top while playing a file on a fresh Squeeze install. 
This behavior is apparently not new[*], and still it is not sure wheter it comes from a broken soundcard driver, alsa, or audacious. But other players do not have such behavior... 

The problem disappears if I change the ALSA Output plugin conf and manually select the PCM device as "front" (Front Speakers), but with this solution other apps are not able to play sound over audacious anymore. The soundcard is not available anymore for them. 

Anyway, while browsing the web[**] I found a workaround: 

Edit ~/.asoundrc and paste this resamplig stuff: 
------------
pcm.!default {
  type plug
  slave.pcm {
    type dmix
    ipc_key 1024
    slave {
       pcm "hw:0,0"
       rate 44100
    }
  }
}
------------

Strange enough? :)

Fabien C. 


[*]  Archived bugs about audacious CPU usage (mid-2009) : #533559, #532081, #588633 
[**] http://boards.audacious-media-player.org/viewtopic.php?f=1&t=193 

-- System Information:
Debian Release: 6.0
  APT prefers squeeze-updates
  APT policy: (500, 'squeeze-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.37 (SMP w/2 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages audacious depends on:
ii  audacious-plugins      2.3+dfsg-1+b1     Base plugins for audacious
ii  dbus                   1.2.24-4          simple interprocess messaging syst
ii  dbus-x11               1.2.24-4          simple interprocess messaging syst
ii  gtk2-engines-pixbuf    2.20.1-2          Pixbuf-based theme for GTK+ 2.x
ii  libatk1.0-0            1.30.0-1          The ATK accessibility toolkit
ii  libaudclient2          2.3-2             audacious dbus remote control libr
ii  libaudcore1            2.3-2             audacious core engine library
ii  libaudid3tag2          2.3-2             audacious id3 tag manipulation lib
ii  libc6                  2.11.2-10         Embedded GNU C Library: Shared lib
ii  libcairo2              1.8.10-6          The Cairo 2D vector graphics libra
ii  libdbus-1-3            1.2.24-4          simple interprocess messaging syst
ii  libdbus-glib-1-2       0.88-2.1          simple interprocess messaging syst
ii  libfontconfig1         2.8.0-2.1         generic font configuration library
ii  libfreetype6           2.4.2-2.1         FreeType 2 font engine, shared lib
ii  libglib2.0-0           2.24.2-1          The GLib library of C routines
ii  libgtk2.0-0            2.20.1-2          The GTK+ graphical user interface 
ii  libice6                2:1.0.6-2         X11 Inter-Client Exchange library
ii  libmcs1                0.7.1-1           Abstraction library to store confi
ii  libmowgli1             0.6.1-1           a high performance development fra
ii  libpango1.0-0          1.28.3-1+squeeze1 Layout and rendering of internatio
ii  libsm6                 2:1.1.1-1         X11 Session Management library

Versions of packages audacious recommends:
ii  unzip                         6.0-4      De-archiver for .zip files

audacious suggests no packages.

-- no debconf information

Message #10 received at 613203@bugs.debian.org (full text, mbox, reply):

From: John Lindgren <john.lindgren@tds.net>

To: "Fabien C." <nsvoaiwvs9bmebb@jetable.org>

Cc: 613203@bugs.debian.org

Subject: Re: audacious: High CPU usage with snd_hda_intel based soundcard

Date: Tue, 15 Feb 2011 10:42:26 -0500

Hi Fabien,

This is indeed a problem that has plagued Audacious on and off for
years.  It is apparently a bug in ALSA's DMix resampler, though still no
one knows exactly what triggers it.  Audacious 2.4.3 has a workaround
(http://hg.atheme.org/release/audacious-plugins-2.4.x/release/audacious-plugins-2.4.x/rev/974307743be7)
that should eliminate the high CPU usage.

-- John

Message #15 received at 613203@bugs.debian.org (full text, mbox, reply):

From: "Fabien C." <nsvoaiwvs9bmebb@jetable.org>

To: John Lindgren <john.lindgren@tds.net>

Cc: 613203@bugs.debian.org

Subject: Re: audacious: High CPU usage with snd_hda_intel based soundcard

Date: Tue, 15 Feb 2011 19:23:39 +0100

Hi John,

Thanks for the info, I should probably report a bug in ALSA in this
case, given the Warning message from the workaround patch...

Fabien C.

PS: Sorry for my first message broken wrapping.

Message #20 received at 613203@bugs.debian.org (full text, mbox, reply):

From: "Fabien C." <nsvoaiwvs9bmebb@jetable.org>

To: John Lindgren <john.lindgren@tds.net>

Cc: 613203@bugs.debian.org

Subject: Re: audacious: High CPU usage with snd_hda_intel based soundcard

Date: Tue, 15 Feb 2011 19:49:04 +0100

Here is the bugreport in the ALSA bugtracker:
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5278

Oh, and I tested with the original Debian kernel as well, and it doesn't
change anything.

Fabien C.

Message #25 received at 613203@bugs.debian.org (full text, mbox, reply):

From: "Fabien C." <nsvoaiwvs9bmebb@jetable.org>

To: John Lindgren <john.lindgren@tds.net>

Cc: 613203@bugs.debian.org

Subject: Re: audacious: High CPU usage with snd_hda_intel based soundcard

Date: Tue, 22 Feb 2011 18:34:13 +0100

> This is indeed a problem that has plagued Audacious on and off for
> years.  It is apparently a bug in ALSA's DMix resampler, though still no
> one knows exactly what triggers it.  Audacious 2.4.3 has a workaround
> (http://hg.atheme.org/release/audacious-plugins-2.4.x/release/audacious-plugins-2.4.x/rev/974307743be7)
> that should eliminate the high CPU usage.

Well, once again it seems that from both sides, it's the other side's fault.

According to comments in ALSA's bugtracker
(https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5278), audacious:
 - does "not calculate the correct buffer size"
 - does not write any data by snd_pcm_writei() or snd_pcm_commit() to the sound
card in alsa_write_audio()

Where are you xmms v1? :)

Message #30 received at 613203@bugs.debian.org (full text, mbox, reply):

From: John Lindgren <john.lindgren@tds.net>

To: "Fabien C." <nsvoaiwvs9bmebb@jetable.org>

Cc: 613203@bugs.debian.org

Subject: Re: audacious: High CPU usage with snd_hda_intel based soundcard

Date: Tue, 22 Feb 2011 12:57:42 -0500

On 02/22/2011 12:34 PM, Fabien C. wrote:
> Well, once again it seems that from both sides, it's the other side's fault.
Though I claim that the root problem lies on the ALSA side, I am not so
arrogant as to refuse to fix it on the Audacious side.  As I mentioned
before, I added a workaround in 2.4.3 that fixes the problem.

> According to comments in ALSA's bugtracker
> (https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5278), audacious:
>  - does "not calculate the correct buffer size"
My understanding, based on much reading of the ALSA docs and discussion
with the ALSA devs, it that ALSA allows applications to set whatever
buffer size they like so that both low-latency applications like games
and high-latency applications like music players can be accommodated. 
By default, Audacious tries to set a buffer size of 250 ms.  Often, the
driver will not allow a buffer this large, in which case Audacious will
look at the actual buffer size set by the driver and adjust for it by
enlarging the software buffer.  This behavior was reached after much
trial and error and after discussion with the ALSA devs.  If Raymond
believes this behavior is wrong, I would like to know why he believes that.

>  - does not write any data by snd_pcm_writei() or snd_pcm_commit() to the sound
> card in alsa_write_audio()
Raymond obviously did not look very long at the code. 
alsa_write_audio(), which is called from the decoding thread, writes
data to the software buffer.  pump(), which runs in its own thread, then
reads data from that buffer and calls snd_pcm_writei().  Raymond's claim
that Audacious does not write any data is clearly ridiculous, because in
that case the problem would not be CPU usage but no audio being played
at all. :)

I would also like to hear why the particular commit that Raymond blames
is at fault.  His claim in this case is ironic, given that that commit
in fact *fixed* another case of high CPU usage with sound drivers that
set a very small period size by default.

-- John Lindgren

Message #37 received at 613203@bugs.debian.org (full text, mbox, reply):

From: Vitalie Lazu <vitalie.lazu@gmail.com>

To: 613203@bugs.debian.org

Subject: High CPU on wav or ape files

Date: Thu, 24 Feb 2011 18:57:14 +0200

Hello,

I also observed this strange behavior today, it happens only on wav
and ape files, it is ok for mp3 format.

-- 
Best regards,
Vitalie

Message #42 received at 613203-done@bugs.debian.org (full text, mbox, reply):

From: Bob Bib <bobbibmpn@mail.ru>

To: 613203-done@bugs.debian.org

Subject: done: audacious: High CPU usage with snd_hda_intel based soundcard

Date: Tue, 31 Jul 2012 01:51:06 +0400

> Bug Marked as fixed in versions audacious/2.4.3-1. Request was from John Lindgren <john.lindgren@tds.net> to control@bugs.debian.org. (Tue, 22 Feb 2011 18:03:04 GMT)

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