nice values and linux/kernel/sched.c

Harald Anlauf (
Thu, 28 Sep 1995 13:02:18 +0100


I was always wondering why one can set process priorities under Linux
only in the range 0..14 (for non-root users). Other *IX'es seem to
allow more "fine-grained" settings in the range 0..20 (or 0..19).
(At least this is what they make their users believe...).

Looking at linux/kernel/sched.c (Kernels 1.2.13 & 1.3.25), I discovered
that the range of settable values is also hard-coded (i.e. not derived
from any header file). Can anybody enlighten me why this is so?

Harald Anlauf, Theoretical High Energy Physics, TH Darmstadt, D-64289 Darmstadt
               Email: <>

It takes all your running you can do to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that. =Lewis Carrol, Through the Looking Glass