Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750930AbWHGPBO (ORCPT ); Mon, 7 Aug 2006 11:01:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750974AbWHGPBM (ORCPT ); Mon, 7 Aug 2006 11:01:12 -0400 Received: from colin.muc.de ([193.149.48.1]:64004 "EHLO mail.muc.de") by vger.kernel.org with ESMTP id S1750930AbWHGPBK (ORCPT ); Mon, 7 Aug 2006 11:01:10 -0400 Date: 7 Aug 2006 17:01:08 +0200 Date: Mon, 7 Aug 2006 17:01:08 +0200 From: Andi Kleen To: Dmitry Torokhov Cc: Vojtech Pavlik , Rusty Russell , lkml - Kernel Mailing List Subject: Re: [PATCH] Turn rdmsr, rdtsc into inline functions, clarify names Message-ID: <20060807150108.GB85602@muc.de> References: <1154771262.28257.38.camel@localhost.localdomain> <1154832963.29151.21.camel@localhost.localdomain> <20060806031643.GA43490@muc.de> <200608062243.45129.dtor@insightbb.com> <20060807084850.GA67713@muc.de> <20060807110931.GM27757@suse.cz> <20060807122845.GA85602@muc.de> <20060807124855.GB21003@suse.cz> <20060807125639.GA88155@muc.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2071 Lines: 48 On Mon, Aug 07, 2006 at 09:32:29AM -0400, Dmitry Torokhov wrote: > On 8/7/06, Andi Kleen wrote: > >On Mon, Aug 07, 2006 at 02:48:55PM +0200, Vojtech Pavlik wrote: > >> On Mon, Aug 07, 2006 at 02:28:45PM +0200, Andi Kleen wrote: > >> > On Mon, Aug 07, 2006 at 01:09:31PM +0200, Vojtech Pavlik wrote: > >> > > On Mon, Aug 07, 2006 at 10:48:50AM +0200, Andi Kleen wrote: > >> > > > On Sun, Aug 06, 2006 at 10:43:44PM -0400, Dmitry Torokhov wrote: > >> > > > > On Saturday 05 August 2006 23:16, Andi Kleen wrote: > >> > > > > > This whole thing is broken, e.g. on a preemptive kernel when > >the > >> > > > > > code can switch CPUs > >> > > > > > > >> > > > > > >> > > > > Would not preempt_disable fix that? > >> > > > > >> > > > Partially, but you still have other problems. Please just get rid > >> > > > of it. Why do we have timer code in the kernel if you then chose > >> > > > not to use it? > >> > > > >> > > The problem is that gettimeofday() is not always fast. > >> > > >> > When it is not fast that means it is not reliable and then you're > >> > also not well off using it anyways. > >> > >> I assume you wanted to say "When gettimeofday() is slow, it means TSC is > >> not reliable", which I agree with. > >> > >> But I need, in the driver, in the no-TSC case use i/o counting, not a > >> slow but reliable method. And I can't say, from outside the timing > >> subsystem, whether gettimeofday() is fast or slow. > > > >Hmm if that is the only obstacle I can export a "slow gettimeofday" flag. > > > >However it would be some work to implement it for all architectures. > > > > Hmm, would it be easier to export "fast gettimeofday" and assume that > we have slow gettimeofday by default (so gameport will fall back on io > counting)? I would expect fast gettimeofday to be more common than slow. -Andi - 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/