From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 2 Aug 2001 13:26:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 2 Aug 2001 13:26:01 -0400 Received: from otter.mbay.net ([206.40.79.2]:6670 "EHLO otter.mbay.net") by vger.kernel.org with ESMTP id convert rfc822-to-8bit; Thu, 2 Aug 2001 13:25:55 -0400 From: jalvo@mbay.net (John Alvord) To: linux-kernel@vger.kernel.org Subject: Re: No 100 HZ timer ! Date: Thu, 02 Aug 2001 17:26:02 GMT Message-ID: <3b6a8c9b.13382832@mail.mbay.net> In-Reply-To: <3B698177.C12183CF@mvista.com> In-Reply-To: <3B698177.C12183CF@mvista.com> X-Mailer: Forte Agent 1.5/32.451 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 02 Aug 2001 09:36:07 -0700, george anzinger wrote: ... > The timing >tests (800MHZ PIII) show the whole setup taking an average of about 1.16 >micro seconds. the problem is that this happens, under kernel compile, >~300 times per second, so the numbers add up. Note that the ticked >system timer overhead (interrupts, time keeping, timers, the works) is >about 0.12% of the available cpu. Under heavy load this raises to about >0.24% according to my measurments. The tick less system overhead under >the same kernel compile load is about 0.12%. No load is about 0.012%, >but heavy load can take it to 12% or more, most of this comming from the >accounting overhead in schedule(). Is it worth it? I thought the claimed advantage was on certain S/390 configurations (running 100s of Linux/390 images under VM) where the cost is multiplied by the number of images. A measurement on another platform may be interesting but not conclusive. john alvord