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Christoph Lameter59121002005-06-23 00:08:25 -07001#
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
Alan Cox40fcfc82006-12-06 20:37:27 -080010 to have the timer interrupt run at 1000 Hz but 100 Hz may be more
Christoph Lameter59121002005-06-23 00:08:25 -070011 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
Alan Cox40fcfc82006-12-06 20:37:27 -080022 100 Hz is a typical choice for servers, SMP and NUMA systems
Christoph Lameter59121002005-06-23 00:08:25 -070023 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
Alan Cox40fcfc82006-12-06 20:37:27 -080029 250 Hz is a good compromise choice allowing server performance
Christoph Lameter59121002005-06-23 00:08:25 -070030 while also showing good interactive responsiveness even
Alan Cox40fcfc82006-12-06 20:37:27 -080031 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.
Christoph Lameter59121002005-06-23 00:08:25 -070041
42 config HZ_1000
43 bool "1000 HZ"
44 help
Alan Cox40fcfc82006-12-06 20:37:27 -080045 1000 Hz is the preferred choice for desktop systems and other
Christoph Lameter59121002005-06-23 00:08:25 -070046 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
Alan Cox40fcfc82006-12-06 20:37:27 -080054 default 300 if HZ_300
Christoph Lameter59121002005-06-23 00:08:25 -070055 default 1000 if HZ_1000
56
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +010057config SCHED_HRTICK
58 def_bool HIGH_RES_TIMERS && X86