A feature for -lowlatency kernel?

[ailo]

I redid my tests, and found the -generic was less reliable for me after
all. ScottL's testing did however show good performance from -generic

There are a few results to be found here:
https://wiki.ubuntu.com/generic_vs_lowlatency_test_results

These tests are still not very adequate, I think. Very practical and
unscientific, but given enough time using the kernels and jackd in lower
latencies, one will probably start to see trends.

On 04/12/2011 05:30 AM, ailo wrote:
> 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