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 Content-Length: 2088 Lines: 50 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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/