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authorChristoph Lameter <christoph@lameter.com>2005-06-23 03:08:25 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-23 12:45:10 -0400
commit59121003721a8fad11ee72e646fd9d3076b5679c (patch)
treec9279c1b74cce81a9dbaf1e7fd038cd55caf26f2 /kernel/Kconfig.hz
parent799d19f6ec5ca2102c61122f5219a17f1c4e961a (diff)
[PATCH] i386: Selectable Frequency of the Timer Interrupt
Make the timer frequency selectable. The timer interrupt may cause bus and memory contention in large NUMA systems since the interrupt occurs on each processor HZ times per second. Signed-off-by: Christoph Lameter <christoph@lameter.com> Signed-off-by: Shai Fultheim <shai@scalex86.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/Kconfig.hz')
-rw-r--r--kernel/Kconfig.hz46
1 files changed, 46 insertions, 0 deletions
diff --git a/kernel/Kconfig.hz b/kernel/Kconfig.hz
new file mode 100644
index 000000000000..248e1c396f8b
--- /dev/null
+++ b/kernel/Kconfig.hz
@@ -0,0 +1,46 @@
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.
32
33 config HZ_1000
34 bool "1000 HZ"
35 help
36 1000 HZ is the preferred choice for desktop systems and other
37 systems requiring fast interactive responses to events.
38
39endchoice
40
41config HZ
42 int
43 default 100 if HZ_100
44 default 250 if HZ_250
45 default 1000 if HZ_1000
46