[LAD] [ANNOUNCE] Safe real-time on the desktop by default; Desktop/audio RT developers, read this!

[Lennart Poettering]

On Mon, 22.06.09 11:15, Fernando Lopez-Lezcano (nando at ccrma.Stanford.EDU) wrote:

> 
> On Mon, 2009-06-22 at 15:38 +0200, Lennart Poettering wrote:
> > On Mon, 22.06.09 15:05, Fons Adriaensen (fons at kokkinizita.net) wrote:
> > 
> > > 
> > > On Mon, Jun 22, 2009 at 09:24:24AM +0100, Bob Ham wrote:
> > > 
> > > > There's something wrong here.
> > > 
> > > There is a lot wrong here.
> > > 
> > > * Question: is the 'demoting' of RT-threads applied only to RT
> > > threads granted by this daeomon, or does it apply to all, including
> > > those created by processes running as root ? In the latter case this
> > > system is not only broken, but should be classified as malware.
> > 
> > Is that so?
> > 
> > It can do both. resetting all is the default.
> 
> Good question. 
> 
> Why is it resetting all the default, even processes with rt privileges
> not granted by RealtimeKit? Isn't rtkit supposed to be the only
> authorized way to access schedulers other that SCHED_OTHER by non-root
> users?

rtkit doesn't need to be the exclusive consumer of the kernel RT
interfaces. RLIMIT_RTPRIO is another supported mechanism that
continues to work.

Even if some folks seem to believe it, I am not replacing anything
existing, shoving down their throats something they didn't need
before. All I do is adding something new, that helps a few desktopish
cases and can be integrated into various applications very easily and
with only minimal impact on dependencies, and is only used as fallback
if nothing else is configured.

Really, I am doing my best to ease adoptions for those interested.
 
> (I assume, for example, that it would not under any circumstances reset
> the scheduler of the kernel interrupt processes in an rt patched
> kernel!!)

By default it only ever looks at non-root processes.

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4