1#
2# Timer Interrupt Frequency Configuration
3#
4
5choice
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
48endchoice
49
50config 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
57config SCHED_HRTICK
58	def_bool HIGH_RES_TIMERS && (!SMP || USE_GENERIC_SMP_HELPERS)
59