pulse-rt by default?

[Lennart Poettering]

On Sun, 05.10.08 17:56, Arjan van de Ven (arjan at infradead.org) wrote:

> > If you add a user to pulse-rt he basically got the power to block the
> > CPU indefinitely and thus freeze the machine.
> > 
> > Unfortunately on Linux we don't have anything in place that would
> > allow "safe" usage of realtime features. There have been steps in the
> > right direction (like real-time group scheduling, RLIMIT_RTTIME), but
> > that is still a royal PITA to use or trivial to circumvent.
>
> yeah it's better to not need realtime, and just have a good enough
> scheduler instead ;-)

I'd love to see something like SCHED_ISO implemented: i.e. where a
process could specify how much CPU time it needs and how often. Would
be ideal for everything that requires a fixed amount of CPU but not
the entire CPU all the time. Would be perfect for video playback,
audio stuff, animations, and everything else.

And that same information would be useful as a replacement for all the
different latency APIs we have on Linux -- if a process says it needs
a bit of CPU every 30th of a second to bring a new movie frame to the
screen then this same information can be used to let the CPU sleep in
some deep sleep state for the rest of the time.

SCHED_ISO wuldn't just solve the security issue. It would also be
immensly useful and a nice API on top.

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
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