Ubuntu Studio Project Lead

Alessio Igor Bogani abogani at ubuntu.com
Sat Jun 12 15:21:31 BST 2010

Hi Brian,

2010/6/11 Brian David <beejunk at gmail.com>:
>> Could you evaluate and compare those results with -lowlatency kernel
>> available on https://launchpad.net/~abogani/+archive/ppa/+packages,
>> please?
> With the -lowlatency kernel, performance was moderate.  Running Hyrdrogen
> through a few JACKRack effects for a little while didn't produce any x-runs
> (except on the program start-up, which is probably to be expected.)
> However, I opened some fairly complicated mixing sessions in Ardour, which
> pushed the DSP to around 40%, and I started getting x-runx every minute or
> so.  This is better than the vanilla kernel, but not quite good enough for
> my needs.
> I tried out the -realtime kernel, and it worked like a charm.  Ran a very
> complicated Ardour session (upwards of 80% DSP) and had not a single x-run
> after 30 minutes.
> I do notice that the kernel page Scott referenced did say to only use the
> -realtime kernel if the other ones do not work.  Is there something I should
> know about this kernel if I plan to use it extensively?  As in, it's not
> going to kill my computer or anything, right?

No -realtime kernel don't kill computers but 1) it don't offer
security fixes, 2) it don't offer a 100% working system with open and
closed video drivers (that is KMS) and 3) Don't offer no one of the
Ubuntu added kernel features (eCrypt, appArmor and so on).

So if you use -realtime you'll obtain a fully preemptible kernel *but*
you could break some other feature.

I would want drop -rt/-realtime kernel because no one seems interested
into it's maintenance and try to make -lowlatency the default kernel
for Studio.


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