Natty and the Real Time Kernel

[laurent.bellegarde]

Hi all tonight here in France,

I've finished my tests on my netbook.

So with last low-latency kernel coming from Alessio PPA, i can run jackd 
+ hydrogen + ardour at 11,4ms, 256 frames /3 periods with an small intel 
onboard sound card on my modest netbook asus eeepc celeron 900 MHz, 2Go 
with natty and unity desktop without any xruns. I'm using 17% of Jackd 
RT power.

on the generic kernel, i've got many xruns as soon as i'm moving a 
window of any program...

Compare to lucid RT kernel running under the same computer, the level of 
performance is quite the same and low-latency kernel could be use for 
production.

An another info, the graphic controller is an old onboard intel i810.

Complete demo and official conference about multimedia with 
ubuntu/ubuntu studio in Paris next saturday in La Villette sciences city 
if the island volcanoe let me fly to Paris ;-)

Some news coming soon.

Bye

Laurent

Le 07/05/2011 08:05, bart deruyter a écrit :
> Hi all,
>
> I've got the same result as Brian David. The generic kernel works 
> quite well, but has xruns, strangely enough, mostly when doing 
> 'nothing'. So far I had no xruns because of recording, mixing, using 
> rakarrack etc... The xruns seem to happen at random.
>
> I do use Unity though, maybe there is something in there that asks 
> some processes which cause the xruns.
>
> My soundcard is an external one, Audiofire 12. jackd is setup at 
> 48000, 256 frames/period and 3 periods/buffer, at a latency of 16 msec.
>
> Running the low-latency kernel eliminates all xruns... I'll definatly 
> keep using it, and I do recommend it too.
>
>
> http://www.bartart3d.be/
>
>
> 2011/5/7 Brian David <beejunk at gmail.com <mailto:beejunk at gmail.com>>
>
>     On Thu, May 5, 2011 at 3:46 AM, Victor henri <nadaeck at hotmail.com
>     <mailto:nadaeck at hotmail.com>> wrote:
>     >
>     > My personal experience is, since 2.6.33, many improvements have
>     been done in
>     > the low latency kernel; I, as several other people, have
>     reported excellent
>     > performances of the 2.6.37 and 2.6.38 low latency kernel, that
>     seemed to get
>     > much closer closer to the rt performance then before. That
>     allows me, most
>     > of the time to not use anymore the RT kernel and all its related
>     problems...
>     >
>
>     I just installed Natty for the first time tonight.  This time around,
>     I went with Xubuntu and installed the Ubuntu Studio packages on top of
>     that.  As Scott mentioned, I needed to add myself to the audio group,
>     but after this my equipment immediately worked.  Unlike previous
>     versions, there was no need to change any configuration files to get
>     access to my firewire device, which means that Ubuntu Studio is
>     basically working out of the box for me now (or, it would be if I had
>     installed from an Ubuntu Studio disc).  Yay!
>
>     For a test run, I did some mixing on a recording I'm working on right
>     now.  I started out using the generic kernel, and performance was
>     surprisingly solid.  There were a few x-runs when starting up or
>     switching between applications, but otherwise it was usable.
>
>     I then installed Allessio's low latency kernel, and proceeded to mix
>     for an hour and half without a single x-run, even when starting up
>     applications and switching between them.  Rock on!  So, I can say
>     definitively that the low latency kernel gives me better performance
>     over generic.
>
>     This test was run at 44.1 khz / 512 frames / 3 periods - getting about
>     34.9 msec latency.  The next time I get the chance, I'll set up some
>     mics and do a recording test at lower latencies (I'll push it to 128
>     frames, which will take it down to 8.71 msec latency.  This is
>     something I have been able to do previously using rt kernels) and see
>     how it performs.
>
>     So far so good.  Thanks for the work, everyone!
>
>
>     --
>     -Brian David
>
>     --
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