AIX Version 4.3 Differences Guide

algorithm. Correspondingly, the CPU delivered to each of the remaining 31
default threads has decreased from 2.5 percent to 2.2 percent.
Table 7. Old Priority Algorithm, sched_R and sched_D Defaulted to 16
nice
delta
Number of threads running (1 niced, others default)
1 2 3 4 5 8 16 32
-20 100 60 47 40 36 30 25 23
-15 100 58 43 36 32 26 21 17
-10 100 55 40 32 28 21 15 13
-5 100 53 37 29 24 17 11 8
0 100 50 33 25 20 13 6 3
5 100 48 30 21 16 7 2 0
10 100 45 27 17 12 4 0 0
15 100 43 23 14 8 0 0 0
19 100 41 21 11 4 0 0 0
Table 8. New Priority Algorithm, sched_R and sched_D Defaulted to 16
nice
delta
Number of threads running (1 niced, others default)
1 2 3 4 5 8 16 32
-20 100 78 60 52 48 42 36 32
-15 100 69 51 43 39 33 26 24
-10 100 60 45 37 32 25 19 16
-5 100 55 39 31 25 19 12 9
0 100 50 33 25 20 13 6 3
5 100 42 24 16 11 4 0 0
10 100 32 17 8 4 0 0 0
15 100 22 11 3 0 0 0 0
19 100 15 6 0 0 0 0 0
It can be seen from the values in Table 9 and Table 10 that decreasing the value
of the sched_R parameter makes the effect of the nice delta even greater. By
reducing the value of sched_R, the priority algorithm places less emphasis on
recently used CPU time. Consequently, the thread with a negative nice delta
receives even more CPU time.
AIX Kernel Enhancements 27