Linux 2.6 doesn't like Rhythmbox

Linux 2.6 doesn't like Rhythmbox

[in7y118]

Hi people,

I'm running Linux 2.6.0-test2 now and found our "itunes clone" Rhythmbox (see 
http://rhythmbox.org) to have choppy playback. Simpler command-line players 
like madplay did not have this problem. (The heavily threaded gst-player had 
this problem, however.) I don't remember having choppy playback with Linux 
2.4.21-preempt either.

Reproducing this is simple if you run Gnome 2 and the snail-fast gnome-terminal:
Get Rhythmbox (I used the 0.4.99.2 prerelease from the website), play some 
sound with it and get your CPU to 100% with a fairly high-prio app (I like to 
switch tabs in gnome-terminal). Sound then starts having hickups.

More or less by accident I was looking at the output of top and found out that 
the audio playback thread had a worse priority than normal (top reported 
between 20 and 25). I then reniced the playback thread to -10 upon thread 
creation and was given problemless playback (top still reported the priority 
going up to 15 again).

Let me explain how threads in Rhythmbox work: The main thread is used for the 
GUI, other threads (mostly idle) take care of the library - reading out 
artist/title/... tags and monitoring file changes so the playlists gets updated 
automagically - and then there is a playback thread. This thread is spawned 
when playback of a file starts (a new one for each file). It starts by 
inspecting the file and constructing a pipeline depending on the file type (ogg 
decoder vs mp3 decoder vs ...). This takes half a second, maybe less. After 
that it proceeds to do read - decode - output to soundcard looping until the 
song is done playing.
The priority according to top starts becoming worse from the beginning of 
playback and gets worse during playback.


My question now is simple: Who shall I blame for this?


Cheers,

Benjamin

Re: Linux 2.6 doesn't like Rhythmbox

[Felipe Alfaro Solana]

On Tue, 2003-08-12 at 16:48, in7y118@public.uni-hamburg.de wrote:

> Let me explain how threads in Rhythmbox work: The main thread is used for the 
> GUI, other threads (mostly idle) take care of the library - reading out 
> artist/title/... tags and monitoring file changes so the playlists gets updated 
> automagically - and then there is a playback thread. This thread is spawned 
> when playback of a file starts (a new one for each file). It starts by 
> inspecting the file and constructing a pipeline depending on the file type (ogg 
> decoder vs mp3 decoder vs ...). This takes half a second, maybe less. After 
> that it proceeds to do read - decode - output to soundcard looping until the 
> song is done playing.
> The priority according to top starts becoming worse from the beginning of 
> playback and gets worse during playback.
> 
> 
> My question now is simple: Who shall I blame for this?

Don't blame anyone still... There's still ongoing kernel scheduler work.
Please, try the latest -mm patches on top of 2.6.0-test3. You will find
them at ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches.

Experiment with 2.6.0-test3-mm1 to see if it still shows the behaviour
you described.

Re: [Rhythmbox-devel] Re: Linux 2.6 doesn't like Rhythmbox

[Colin Walters]

On Tue, 2003-08-12 at 12:05, Felipe Alfaro Solana wrote:

> Don't blame anyone still... There's still ongoing kernel scheduler work.
> Please, try the latest -mm patches on top of 2.6.0-test3. You will find
> them at ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches.
> 
> Experiment with 2.6.0-test3-mm1 to see if it still shows the behaviour
> you described.

Yeah, I had a great experience with 2.6.0-test2-mm for interactivity;
Rhythmbox almost never skipped.  However I had to go back to 2.4.21
because APM stopped working in 2.6.0-test2-mm, and ACPI never worked
(both freeze on startup).  -test3 didn't help either...

Re: Linux 2.6 doesn't like Rhythmbox

[in7y118]

Quoting Felipe Alfaro Solana <felipe_alfaro@linuxmail.org>:

> Don't blame anyone still... There's still ongoing kernel scheduler work.
> Please, try the latest -mm patches on top of 2.6.0-test3. You will find
> them at ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches.
> 
> Experiment with 2.6.0-test3-mm1 to see if it still shows the behaviour
> you described.
> 
I tried it. -test3-mm1 works perfectly fine with Rhythmbox. X was a bit slow to 
update sometimes under heavy load, but I guess that's known.
Stock -test3 showed the same bda behaviour as -test2 though.

The only thing I don't want is users telling me my apps suck. So I thought 
alerting would be better than waiting for distributions to ship those kernels.


Thanks
Benjamin