Lines Matching refs:nice

2 nice-levels implementation in the new Linux scheduler.
5 pestered us to make nice +19 tasks use up much less CPU time.
8 scheduler, (otherwise we'd have done it long ago) because nice level
12 In the O(1) scheduler (in 2003) we changed negative nice levels to be
15 rule so that nice +19 level would be _exactly_ 1 jiffy. To better
30  -*----------------------------------*-----> [nice level]
45 people were running number crunching apps at nice +19.)
47 So for HZ=1000 we changed nice +19 to 5msecs, because that felt like the
49 But the fundamental HZ-sensitive property for nice+19 still remained,
50 and we never got a single complaint about nice +19 being too _weak_ in
54 To sum it up: we always wanted to make nice levels more consistent, but
59 about Linux's nice level support was its assymetry around the origo
61 accurately: the fact that nice level behavior depended on the _absolute_
62 nice level as well, while the nice API itself is fundamentally
65    int nice(int inc);
70 Note that the 'inc' is relative to the current nice level. Tools like
71 bash's "nice" command mirror this relative API.
75 depend on the nice level of the parent shell - if it was at nice -10 the
78 A third complaint against Linux's nice level support was that negative
79 nice levels were not 'punchy enough', so lots of people had to resort to
86 To address the first complaint (of nice levels being not "punchy"
88 (and granularity was made a separate concept from nice levels) and thus
89 it was possible to implement better and more consistent nice +19
90 support: with the new scheduler nice +19 tasks get a HZ-independent
94 To address the second complaint (of nice levels not being consistent),
95 the new scheduler makes nice(1) have the same CPU utilization effect on
96 tasks, regardless of their absolute nice levels. So on the new
97 scheduler, running a nice +10 and a nice 11 task has the same CPU
98 utilization "split" between them as running a nice -5 and a nice -4
99 task. (one will get 55% of the CPU, the other 45%.) That is why nice
101 it does not matter which nice level you start out from, the 'relative
104 The third complaint (of negative nice levels not being "punchy" enough
107 automatically: stronger negative nice levels are an automatic
108 side-effect of the recalibrated dynamic range of nice levels.