Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265059AbUAGGaa (ORCPT ); Wed, 7 Jan 2004 01:30:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266136AbUAGGaa (ORCPT ); Wed, 7 Jan 2004 01:30:30 -0500 Received: from smtp809.mail.sc5.yahoo.com ([66.163.168.188]:22165 "HELO smtp809.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S265059AbUAGGa2 (ORCPT ); Wed, 7 Jan 2004 01:30:28 -0500 From: Dmitry Torokhov To: john stultz Subject: Re: [2.6.0-mm2] PM timer still has problems Date: Wed, 7 Jan 2004 01:30:21 -0500 User-Agent: KMail/1.5.4 Cc: Karol Kozimor , Andrew Morton , lkml , Arjan van de Ven , jw schultz References: <20031230204831.GA17344@hell.org.pl> <200401050117.06681.dtor_core@ameritech.net> <1073377877.2752.38.camel@localhost> In-Reply-To: <1073377877.2752.38.camel@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200401070130.21769.dtor_core@ameritech.net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1371 Lines: 29 On Tuesday 06 January 2004 03:31 am, john stultz wrote: > On Sun, 2004-01-04 at 22:17, Dmitry Torokhov wrote: > > I decided to go hpet way and use tsc in ACPI PM timer to do delay > > stuff and monotonic clock. > > I think you have a valid point that as loops_per_jiffy isn't updated, > delay_pmtmr() and delay_pit() are broken w/ CPUFREQ. > > However I don't understand using the TSC for montonic_clock. I have no > clue why the HPET folks implemented it that way (likely my fault for > not enough documentaiton), but I haven't had the time to try to clean > up that code. And really, if your TSC is reliable enough for > monotonic_clock, why are you using the pmtmr? :) Unless it specifically > is resolving an issue, I'd drop that change. > I thought (it seems that I was mistaken) that the goal of monotonic_clock is to privide high-resolution cheap timestamps that are guaranteed never go back as there is no adjustments to the time. The normal clock it supposed to be stable and accurate but probably give lower resolution. In case of pmtmr vs. TSC seems to have higher resolution and is cheap so it was used. Dmitry - 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/