arritt@kuhub.cc.ukans.edu (07/03/90)
I am using a 4D/25G running IRIX 3.2. The "nice" command does not seem
to do what I would like; i.e., establish varying priorities for different
jobs. Specifically it does not seem to respond to the priority increment
argument. As a test, I started three identical jobs, as follows:
JOB 1: ascot.exe < ascot.dat > ascot.out &
JOB 2: nice -19 ascot.exe < ascot.dat > ascot.nice &
JOB 3: nice ascot.exe < ascot.dat > ascot.nice2 &
I then checked the jobs every so often, and found the following cpu usage:
JOB 1 (change from previous) JOB 2 (change) JOB 3 (change)
4:34 1:49 0:01
4:51 (0:17) 2:07 (0:18) 0:16 (0:15)
5:13 (0:22) 2:30 (0:23) 0:35 (0:19)
5:41 (0:28) 2:57 (0:27) 0:57 (0:18)
As you can see from the (change) entries, JOB 1 and JOB 2 used the same cpu
within roundoff error to one second, while JOB 3 uses less cpu. I would have
expected for JOB 2 to get the least cpu (at "nice -19"), JOB 3 to get a little
more (since "nice" should default to "nice -10") and JOB 1 to get the most.
Each job is 397 blocks (about 1.6 MB) so all three jobs should fit easily into
the system's 16 MB of physical memory.
What am I doing wrong? Any help you can give would be most appreciated.
________________________________________________________________________
Ray Arritt |
Dept. of Physics and Astronomy |
Univ. of Kansas |
Lawrence, KS 66045 |
arritt@kuhub.cc.ukans.edu |
arritt@ukanvax.bitnet |