Merge remote-tracking branch 'rcu/rcu/next'
[deliverable/linux.git] / kernel / Kconfig.hz
1 #
2 # Timer Interrupt Frequency Configuration
3 #
4
5 choice
6 prompt "Timer frequency"
7 default HZ_250
8 help
9 Allows the configuration of the timer frequency. It is customary
10 to have the timer interrupt run at 1000 Hz but 100 Hz may be more
11 beneficial for servers and NUMA systems that do not need to have
12 a fast response for user interaction and that may experience bus
13 contention and cacheline bounces as a result of timer interrupts.
14 Note that the timer interrupt occurs on each processor in an SMP
15 environment leading to NR_CPUS * HZ number of timer interrupts
16 per second.
17
18
19 config HZ_100
20 bool "100 HZ"
21 help
22 100 Hz is a typical choice for servers, SMP and NUMA systems
23 with lots of processors that may show reduced performance if
24 too many timer interrupts are occurring.
25
26 config HZ_250
27 bool "250 HZ"
28 help
29 250 Hz is a good compromise choice allowing server performance
30 while also showing good interactive responsiveness even
31 on SMP and NUMA systems. If you are going to be using NTSC video
32 or multimedia, selected 300Hz instead.
33
34 config HZ_300
35 bool "300 HZ"
36 help
37 300 Hz is a good compromise choice allowing server performance
38 while also showing good interactive responsiveness even
39 on SMP and NUMA systems and exactly dividing by both PAL and
40 NTSC frame rates for video and multimedia work.
41
42 config HZ_1000
43 bool "1000 HZ"
44 help
45 1000 Hz is the preferred choice for desktop systems and other
46 systems requiring fast interactive responses to events.
47
48 endchoice
49
50 config HZ
51 int
52 default 100 if HZ_100
53 default 250 if HZ_250
54 default 300 if HZ_300
55 default 1000 if HZ_1000
56
57 config SCHED_HRTICK
58 def_bool HIGH_RES_TIMERS
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