From 59121003721a8fad11ee72e646fd9d3076b5679c Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Thu, 23 Jun 2005 00:08:25 -0700 Subject: [PATCH] [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 Signed-off-by: Shai Fultheim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/Kconfig | 2 ++ arch/x86_64/Kconfig | 2 ++ include/asm-i386/param.h | 4 +++- include/asm-x86_64/param.h | 6 +++-- kernel/Kconfig.hz | 46 ++++++++++++++++++++++++++++++++++++++ 5 files changed, 57 insertions(+), 3 deletions(-) create mode 100644 kernel/Kconfig.hz 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 If unsure, say Y. Only embedded should say N here. +source kernel/Kconfig.hz + endmenu 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 If unsure, say Y. Only embedded should say N here. +source kernel/Kconfig.hz + endmenu # 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 @@ +#include + #ifndef _ASMi386_PARAM_H #define _ASMi386_PARAM_H #ifdef __KERNEL__ -# define HZ 1000 /* Internal kernel timer frequency */ +# define HZ CONFIG_HZ /* Internal kernel timer frequency */ # define USER_HZ 100 /* .. some user interfaces are in "ticks" */ # define CLOCKS_PER_SEC (USER_HZ) /* like times() */ #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 @@ +#include + #ifndef _ASMx86_64_PARAM_H #define _ASMx86_64_PARAM_H #ifdef __KERNEL__ -# define HZ 1000 /* Internal kernel timer frequency */ -# define USER_HZ 100 /* .. some user interfaces are in "ticks */ +# define HZ CONFIG_HZ /* Internal kernel timer frequency */ +# define USER_HZ 100 /* .. some user interfaces are in "ticks */ #define CLOCKS_PER_SEC (USER_HZ) /* like times() */ #endif 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 @@ +# +# Timer Interrupt Frequency Configuration +# + +choice + prompt "Timer frequency" + default HZ_250 + help + Allows the configuration of the timer frequency. It is customary + to have the timer interrupt run at 1000 HZ but 100 HZ may be more + beneficial for servers and NUMA systems that do not need to have + a fast response for user interaction and that may experience bus + contention and cacheline bounces as a result of timer interrupts. + Note that the timer interrupt occurs on each processor in an SMP + environment leading to NR_CPUS * HZ number of timer interrupts + per second. + + + config HZ_100 + bool "100 HZ" + help + 100 HZ is a typical choice for servers, SMP and NUMA systems + with lots of processors that may show reduced performance if + too many timer interrupts are occurring. + + config HZ_250 + bool "250 HZ" + help + 250 HZ is a good compromise choice allowing server performance + while also showing good interactive responsiveness even + on SMP and NUMA systems. + + config HZ_1000 + bool "1000 HZ" + help + 1000 HZ is the preferred choice for desktop systems and other + systems requiring fast interactive responses to events. + +endchoice + +config HZ + int + default 100 if HZ_100 + default 250 if HZ_250 + default 1000 if HZ_1000 +