Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 13 Oct 2002 06:36:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 13 Oct 2002 06:36:05 -0400 Received: from mailout03.sul.t-online.com ([194.25.134.81]:40123 "EHLO mailout03.sul.t-online.com") by vger.kernel.org with ESMTP id ; Sun, 13 Oct 2002 06:36:05 -0400 Message-ID: <3DA94F07.7070109@t-online.de> Date: Sun, 13 Oct 2002 12:46:31 +0200 From: Ingo.Adlung@t-online.de (Ingo Adlung) User-Agent: Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 X-Accept-Language: en-us, en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org CC: "Linus Torvalds" <"Linus Torvalds"@t-online.de> Subject: Re: [PATCH 2/3] High-res-timers part 2 (x86 platform code) take 5.1 References: <3DA4B1EC.781174A6@mvista.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1458 Lines: 37 Linus Torvalds wrote: > On Wed, 9 Oct 2002, george anzinger wrote: > >>This patch, in conjunction with the "core" high-res-timers >>patch implements high resolution timers on the i386 >>platforms. > > > I really don't get the notion of partial ticks, and quite frankly, this > isn't going into my tree until some major distribution kicks me in the > head and explains to me why the hell we have partial ticks instead of just > making the ticks shorter. > > Linus In any kind of virtual environment you would rather prefer a completely tickless system alltogether than increased tick rates. In a S/390 virtual machine, running many hundreds of virtual Linux servers the 100Hz timer pops are already considerably painful, and going to a higher tick rate achieving higher timer resolution is completely prohibitive. Similar is true in many embedded systems related to power consumption of high frequency ticks. However, George has shown that introducing the notion of a completely tickless system is expensive on Intel overhead wise, thus partial ticks seem to be a possibility addressing the needs for embedded and virtual environments, getting decent timer resolution as needed. Ingo Adlung - 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/