[AG-TECH] AccessGrid 3: What information is available

shudo at ni.aist.go.jp shudo at ni.aist.go.jp
Tue May 24 12:30:27 CDT 2005

From: Colin Perkins <csp at csperkins.org>

> >> And assuming that the OS was a realtime OS and thus could actually  
> >> provide timing assurances to applications.
> >
> > I know as of a couple years ago the hardcore linux audio folks were
> > doing exactly this; I don't know the current state of the realtime
> > mods for linux.

> but for rat we intentionally ignored this support, since it
> exposes a number of security issues (you have to make the application
> suid root and carefully drop privileges after enabling real-time
> scheduling) and didn't seem to offer much benefit.

I guess the above mentioned one is POSIX.1b scheduling interface
(i.e. sched_setscheduler(2) syscall).  AFAIK, it is not really related
to real-time scheduling and it is just a meaning to give higher
priority (1-99) to special processes than usual processes (priority 0).
Real "real-time scheduling" involves timing deadlines, but the POSIX
scheduling interface does not concern the concept of deadline at all.

Yes, it improved stability of MP3 playing on my Linux box several
years ago as you mentioned and it requires root priviledges.

  Kazuyuki Shudo
  Grid Technology Research Center
  National Institute of Advanced Industrial Science and Technology (AIST)

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