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