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

Lennart Poettering mzynq at 0pointer.de
Mon Jun 22 15:34:11 UTC 2009

On Mon, 22.06.09 10:08, Paul Davis (paul at linuxaudiosystems.com) wrote:

> Lennart, I am still trying to understand what the basic rationale is
> here. 3 years ago, the kernel mailing discussed RT scheduling and
> decided that RLIMIT_RTPRIO was the way to handle access to this
> capability. That decision was made knowing that some user-space
> infrastructure would be necessary to make it usable for most
> end-users. So, 3 years on, that user space infrastructure hasn't been
> created, and now your proposed solution is to provide a different
> method of accessing RT scheduling. Are you arguing/suggesting that the
> user-space infrastructure will never be created because of the
> security issues? 

What exactly are you asking for as "user-space infrastructure"? Some
easy to reach UI that will allow you to make yourself a member of some
group? This is unlikely to happen. At least not from the desktop

I mean, rtkit is user-space infrastructure, so what are you asking for
that isn't covered by rtkit?

> Are you suggesting that the original decision to focus on
> RLIMIT_RTPRIO was a mistake that didn't take "the reality of what
> mainstream distros will do" into account?

Yes. I guess you can say that. Although I wouldn't call it a
"mistake". RLIMIT_RTPRIO was added with audio production in
mind. While I think even then it sucks UI-wise, it certainly was good
enough and better than anything there was before. 

However, as soon as we want to make RT available out-of-the-box
RLIMIT_RTPRIO just doesn't cut it.


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

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