Re: Candidate multi-console friendly 2.6 scheduling?

[James v. Z. <ja...@dv...>]

> Running the important program at realtime priority wil take care of even the
> scheduling differences, but requires root privileges.

ruby.vz kernel includes realtime LSM which allows non-root users to
request realtime priviledges. select default capabilities as a module
and realtime capabilities will appear as an option.
possibly real security risk. PlanetCCRMA includes sys-v init tools for
handling load/unload of realtime module, realtime capabilities can be
spcified by user-ID or Any.

For me this is necessary for compatibility with jack audio connection
kit and lowest latency audio performance.

Config_Hz is also available in kernel config

J


On Thu, 2005-01-13 at 09:16, Helge Hafting wrote:
> On Wed, Jan 12, 2005 at 04:40:05AM -0800, Hugo Vanwoerkom wrote:
> > 
> > But I don't use top: wrote my own code: get it from
> > /proc/<pid>/stat
> > Is that data bad too?
> > 
> Accuracy varies a lot between 2.4 and 2.6, due to the changed timer.
> The worst case is processes that do periodically work with
> short sleeps in between.  
> 
> If you want a good idea about how much "idle" time there is, do this:
> 1. Run your apps at normal priority for some time.
> 2. Run a cpu hog, something like  " for (i=0;;) ++i;" at the lowest
>    possible priority.   Then check to see how much "work" the cpu
>    hog manages to do (how far did it count, watch out for wraparound)
>    in a given amount of time while the other stuff was running.
> 
> If the cpu hog gets less works done under 2.6, then you can say that
> 2.6 has more overhead (or at least a different take on
> priority-based scheduling).  
> 
> Running the important program at realtime priority wil take care of even the
> scheduling differences, but requires root privileges.
> 
> Helge Hafting 
>