Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263810AbUDVK7J (ORCPT ); Thu, 22 Apr 2004 06:59:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263933AbUDVK7J (ORCPT ); Thu, 22 Apr 2004 06:59:09 -0400 Received: from mtagate3.de.ibm.com ([195.212.29.152]:3290 "EHLO mtagate3.de.ibm.com") by vger.kernel.org with ESMTP id S263810AbUDVKxg (ORCPT ); Thu, 22 Apr 2004 06:53:36 -0400 Subject: Re: [PATCH] s390 (9/9): no timer interrupts in idle. To: Arjan van de Ven Cc: akpm@osdl.org, linux-kernel@vger.kernel.org X-Mailer: Lotus Notes Release 5.0.11 July 24, 2002 Message-ID: From: Martin Schwidefsky Date: Thu, 22 Apr 2004 12:53:15 +0200 X-MIMETrack: Serialize by Router on D12ML062/12/M/IBM(Release 6.0.2CF2|July 23, 2003) at 22/04/2004 12:53:17 MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 949 Lines: 28 > well my worry is the API; should it be "turn the timer off" or should it be > "the next tick is THIS many from now". The later allows one to use the hw in > one-shot mode (PC's can do this) where the scheduler timeslice expiry ends > up being a timer as well. The sysctl is /proc/sys/kernel/hz_timer. If it contains a "1" then HZ timer is active in idle, a "0" indicates that the HZ timer is switchted off. The semantic "the next tick is THIS many from now" IHMO doesn't make any sense. Skipping ticks will have some really bad effects, e.g. if the xtime isn't up-to-date network packets will get incorrect time stamps, timer events will be delivered too late, etc. blue skies, Martin - 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/