xref: /openbmc/linux/kernel/Kconfig.hz (revision ec8f24b7)
1# SPDX-License-Identifier: GPL-2.0-only
2#
3# Timer Interrupt Frequency Configuration
4#
5
6choice
7	prompt "Timer frequency"
8	default HZ_250
9	help
10	 Allows the configuration of the timer frequency. It is customary
11	 to have the timer interrupt run at 1000 Hz but 100 Hz may be more
12	 beneficial for servers and NUMA systems that do not need to have
13	 a fast response for user interaction and that may experience bus
14	 contention and cacheline bounces as a result of timer interrupts.
15	 Note that the timer interrupt occurs on each processor in an SMP
16	 environment leading to NR_CPUS * HZ number of timer interrupts
17	 per second.
18
19
20	config HZ_100
21		bool "100 HZ"
22	help
23	  100 Hz is a typical choice for servers, SMP and NUMA systems
24	  with lots of processors that may show reduced performance if
25	  too many timer interrupts are occurring.
26
27	config HZ_250
28		bool "250 HZ"
29	help
30	 250 Hz is a good compromise choice allowing server performance
31	 while also showing good interactive responsiveness even
32	 on SMP and NUMA systems. If you are going to be using NTSC video
33	 or multimedia, selected 300Hz instead.
34
35	config HZ_300
36		bool "300 HZ"
37	help
38	 300 Hz is a good compromise choice allowing server performance
39	 while also showing good interactive responsiveness even
40	 on SMP and NUMA systems and exactly dividing by both PAL and
41	 NTSC frame rates for video and multimedia work.
42
43	config HZ_1000
44		bool "1000 HZ"
45	help
46	 1000 Hz is the preferred choice for desktop systems and other
47	 systems requiring fast interactive responses to events.
48
49endchoice
50
51config HZ
52	int
53	default 100 if HZ_100
54	default 250 if HZ_250
55	default 300 if HZ_300
56	default 1000 if HZ_1000
57
58config SCHED_HRTICK
59	def_bool HIGH_RES_TIMERS
60