Re: [PATCH] [request for inclusion] Realtime LSM

Takashi Iwai
2005-01-07T16:20:31Z

At Fri, 7 Jan 2005 17:03:51 +0100,
Arjan van de Ven wrote:
>
> On Fri, Jan 07, 2005 at 10:41:40AM -0500, Paul Davis wrote:
> >
> > fine, so the mlock situation may have improved enough post-2.6.9 that
> > it can be considered fixed. that leaves the scheduler issue. but
> > apparently, a uid/gid solution is OK for mlock, and not for the
> > scheduler. am i missing something?
>
> I think you skipped a step. You don't have a scheduler requirement, you have
> a latency requirement. You currently *solve* that latency requirement via a
> scheduler "hack", yet is quite clear that the "hard" realtime solution is
> most likely not the right approach. Note that I'm not saying that you
> shouldn't get the latency that that currently provides, but the downsides
> (can hang the machine) are bad; a solution that solves that would be far
> preferable
> something like a soft realtime flag that acts as if it's the hard realtime
> one unless the app shows "misbehavior" (eg eats its timeslice for X times in
> a row) might for example be such a solution. And with the anti abuse
> protection it can run with far lighter privilegs.

This reminds me about the soft-RT patch posted quite sometime ago.
I feel such a handy psuedo-RT scheduler class would be useful for
other systems than JACK, too...

Takashi