aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
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
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>
-rw-r--r--arch/i386/Kconfig2
-rw-r--r--arch/x86_64/Kconfig2
-rw-r--r--include/asm-i386/param.h4
-rw-r--r--include/asm-x86_64/param.h6
-rw-r--r--kernel/Kconfig.hz46
5 files changed, 57 insertions, 3 deletions
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index bfdcedef06e1..d4ae5f9ceae6 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -961,6 +961,8 @@ config SECCOMP
961 961
962 If unsure, say Y. Only embedded should say N here. 962 If unsure, say Y. Only embedded should say N here.
963 963
964source kernel/Kconfig.hz
965
964endmenu 966endmenu
965 967
966 968
diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index 61ed16652347..db259757dc8a 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -402,6 +402,8 @@ config SECCOMP
402 402
403 If unsure, say Y. Only embedded should say N here. 403 If unsure, say Y. Only embedded should say N here.
404 404
405source kernel/Kconfig.hz
406
405endmenu 407endmenu
406 408
407# 409#
diff --git a/include/asm-i386/param.h b/include/asm-i386/param.h
index b6440526e42a..fa02e67ea86b 100644
--- a/include/asm-i386/param.h
+++ b/include/asm-i386/param.h
@@ -1,8 +1,10 @@
1#include <linux/config.h>
2
1#ifndef _ASMi386_PARAM_H 3#ifndef _ASMi386_PARAM_H
2#define _ASMi386_PARAM_H 4#define _ASMi386_PARAM_H
3 5
4#ifdef __KERNEL__ 6#ifdef __KERNEL__
5# define HZ 1000 /* Internal kernel timer frequency */ 7# define HZ CONFIG_HZ /* Internal kernel timer frequency */
6# define USER_HZ 100 /* .. some user interfaces are in "ticks" */ 8# define USER_HZ 100 /* .. some user interfaces are in "ticks" */
7# define CLOCKS_PER_SEC (USER_HZ) /* like times() */ 9# define CLOCKS_PER_SEC (USER_HZ) /* like times() */
8#endif 10#endif
diff --git a/include/asm-x86_64/param.h b/include/asm-x86_64/param.h
index b707f0568c9e..40b11937180d 100644
--- a/include/asm-x86_64/param.h
+++ b/include/asm-x86_64/param.h
@@ -1,9 +1,11 @@
1#include <linux/config.h>
2
1#ifndef _ASMx86_64_PARAM_H 3#ifndef _ASMx86_64_PARAM_H
2#define _ASMx86_64_PARAM_H 4#define _ASMx86_64_PARAM_H
3 5
4#ifdef __KERNEL__ 6#ifdef __KERNEL__
5# define HZ 1000 /* Internal kernel timer frequency */ 7# define HZ CONFIG_HZ /* Internal kernel timer frequency */
6# define USER_HZ 100 /* .. some user interfaces are in "ticks */ 8# define USER_HZ 100 /* .. some user interfaces are in "ticks */
7#define CLOCKS_PER_SEC (USER_HZ) /* like times() */ 9#define CLOCKS_PER_SEC (USER_HZ) /* like times() */
8#endif 10#endif
9 11
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