linuxaudio.org

On Sun, 2010-07-11 at 17:21 +0200, Arnout Engelen wrote:

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> On Sun, Jul 11, 2010 at 04:53:14PM +0200, Ralf Mardorf wrote:

> > today I compared a default Ubuntu Studio with and without the

> > proprietary NVIDIA driver.

>

> OK, so the proprietary driver seems to yield better 'worst latency' values

> compared to nouveau. That's kind of odd, anything X-related would have a much

> lower priority than the MIDI threads.

>

> > Note that for Ubuntu Studio 2 tests failed because of time out errors

>

> What exactly timed out?

There was a time out message by the alsa-midi-latency-test. It started

and than it asked, if there still is a connection, while there still was

a connection.
>

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> > even the tests that were passed with success are significantly less good,

> > than the tests with openSUSE, were I set up audio myself.

> >

> > What might be the difference between Ubuntu and Suse?

>

> > ------------------------------------------------------------------------

> > Ubuntu Studio 10.04 amd64

> > 2 x Terratec EWX 24/96 (2 single cards, but 1 virtual card)

> > Frequency scaling ?

> > ------------------------------------------------------------------------

> > spinymouse@ubuntu:~$ uname -a

> > Linux ubuntu 2.6.32-23-preempt #37-Ubuntu SMP PREEMPT Fri Jun 11

> > 10:19:07 UTC 2010 x86_64 GNU/Linux

> > spinymouse@ubuntu:~$ envy24control

> > 0xcf00, irq 20, Master Clock int 44100

>

> > ------------------------------------------------------------------------

> > openSUSE 11.2 amd64

> > 2 x Terratec EWX 24/96 (2 single cards, but 1 virtual card)

> > Frequency scaling performance

> > ------------------------------------------------------------------------

> > spinymouse11.2@suse11-2:~> uname -a

> > Linux suse11-2 2.6.31.6-rt19 #1 SMP PREEMPT RT Wed Nov 18 16:59:26 CET

> > 2009 x86_64 x86_64 x86_64 GNU/Linux

>

> 2 differences jump out:

>

> - the frequency scaling is set to 'performance' on your suse install and to

>   '?' on your ubuntu install.

Yes, I assume that an audio distro won't start with ondemand by default,

I'll run hwinfo to see the scaling next time. For Ubuntu Studio there

are a lot of issues that are nwe to me, no xorg.conf, no menu.lst etc..
> - The kernel options for your suse install has the options 'SMP PREEMPT RT',

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>   while your ubuntu install has the options 'SMP PREEMPT'. In other words, it

>   looks like your ubuntu kernel has 'normal' preemption, but not the -rt

>   patch.

I didn't noticed that, you're right. The Suse kernel is self build, the

Ubuntu Studio kernel is from the repositories.
> The latter looks like a good candidate for explaining the difference. Could

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> you test with the kernel from the linux-image-2.6.31-10-rt package instead of

> the kernel from the linux-image-2.6.32-21-preempt package which you seem to be

> using now?

Thank you, a good idea, before I'll build a kernel by myself, it would

take around 50 minutes, I'll install this kernel from the repository.
To be continued.
Ralf
>

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>

> Kind regards,

>

> Arnout

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