From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261852AbVEPUnu (ORCPT ); Mon, 16 May 2005 16:43:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261865AbVEPUnt (ORCPT ); Mon, 16 May 2005 16:43:49 -0400 Received: from serv01.siteground.net ([70.85.91.68]:60076 "EHLO serv01.siteground.net") by vger.kernel.org with ESMTP id S261852AbVEPUnj (ORCPT ); Mon, 16 May 2005 16:43:39 -0400 Date: Mon, 16 May 2005 12:45:29 -0700 (PDT) From: christoph X-X-Sender: christoph@ScMPusgw To: linux-kernel@vger.kernel.org cc: shai@scalex86.org, akpm@osdl.org Subject: [PATCH] i386: Selectable Frequency of the Timer Interrupt. Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - serv01.siteground.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [0 0] / [47 12] X-AntiAbuse: Sender Address Domain - scalex86.org X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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 Index: linux-2.6.11/arch/i386/Kconfig =================================================================== --- linux-2.6.11.orig/arch/i386/Kconfig 2005-05-16 12:07:31.000000000 -0700 +++ linux-2.6.11/arch/i386/Kconfig 2005-05-16 12:39:48.000000000 -0700 @@ -939,6 +939,20 @@ config SECCOMP If unsure, say Y. Only embedded should say N here. +config HZ + int "Frequency of the Timer Interrupt (1000 or 100)" + range 100 1000 + default 1000 + 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. + endmenu Index: linux-2.6.11/include/asm-i386/param.h =================================================================== --- linux-2.6.11.orig/include/asm-i386/param.h 2005-05-16 12:07:25.000000000 -0700 +++ linux-2.6.11/include/asm-i386/param.h 2005-05-16 12:09:04.000000000 -0700 @@ -2,7 +2,7 @@ #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