A feature for -lowlatency kernel?

[ailo]

Pointless but funny test result from trying -lowlatency on AMD64 with
M-Audio 1010LT:

jackd -d alsa -d hw:1 -p 16 -n 2 -r 96000

Latency showed in qjackctl at 0.333 ms. I get a few xruns, but not as
many as one would think. Not usable with audio programs, though.

------------------------------------

My initial tests on two machines (for a somewhat lengthy period of time):

*-lowlatency*

Kernel: linux-lowlatency 2.6.39-0
System: Intel dual core 2.13GHz
Sound Device: HDA Intel (onboard)
Session: Simple Ardour and puredata usage
Lowest reliable jackd setting(without xruns): jackd -d alsa -p 64 / 2.9 ms

Kernel: linux-lowlatency 2.6.39-0
System: AMD Athlon X2 245
Sound Device: M-Audio 1010LT
Session: Simple Ardour usage
Lowest reliable jackd setting: jackd -d alsa -p 32 / 1.45 ms

*-generic*

Kernel: linux-generic 2.6.38-8
System: Intel dual core 2.13GHz
Sound Device: HDA Intel (onboard)
Session: Simple Ardour and puredata usage
Lowest reliable jackd setting(without xruns): jackd -d alsa -p 64 / 2.9 ms

Kernel: linux-lowlatency 2.6.38-8
System: AMD Athlon X2 245
Sound Device: M-Audio 1010LT
Session: Simple Ardour usage
Lowest reliable jackd setting: jackd -d alsa -p 256 / 11.6 ms

--------------------------

What is remarkable is how -generic and -lowlatency seem equal on the
Intel dual core, using the onboard sound device, while there is a huge
difference on the AMD64 machine with M-Audio 1010LT.







On 04/11/2011 02:12 PM, Alessio Igor Bogani wrote:
> Dear Ubuntu Studio Developers,
> 
> 2011/3/25 Alessio Igor Bogani <abogani at ubuntu.com>:
> [...]
>>> So I could provide a -lowlatency kernel based on 39 kernel if enough
>>> testers will offer theirs help. Sincerely I would want avoid to waste
>>> time for make something that no one will use.
> [...]
> 
> You can find the 39-lowlatency(*) kernel at
> https://launchpad.net/~abogani/+archive/snmp++/+packages
> I suggest to install it manually (so without add the PPA).
> 
> Now it's your turn testers! :-)
> 
> Ciao,
> Alessio
> 
> (*) Irq-threaded by default
> 


-- 
ailo