Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759070AbXEROvU (ORCPT ); Fri, 18 May 2007 10:51:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754665AbXEROvO (ORCPT ); Fri, 18 May 2007 10:51:14 -0400 Received: from h155.mvista.com ([63.81.120.155]:31502 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1754315AbXEROvN (ORCPT ); Fri, 18 May 2007 10:51:13 -0400 Message-ID: <464DBDBA.3060801@ru.mvista.com> Date: Fri, 18 May 2007 18:52:42 +0400 From: Sergei Shtylyov Organization: MontaVista Software Inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; rv:1.7.2) Gecko/20040803 X-Accept-Language: ru, en-us, en-gb MIME-Version: 1.0 To: Albert Cahalan Cc: galak@kernel.crashing.org, tglx@linutronix.de, linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver References: <787b0d920705172024g723412b4n8f82d3cd78e0f702@mail.gmail.com> In-Reply-To: <787b0d920705172024g723412b4n8f82d3cd78e0f702@mail.gmail.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: 1475 Lines: 38 Hello. Albert Cahalan wrote: >>>>> I haven't looked at all the new clock/timer code, is there any >>>>> utility in having support for more than one clock source? >>>> Of course, you may register as many as you like. >>> Sure, but is there any utility in registering more than the >>> decrementer on PPC? >> Not yet. I'm not sure I know any other PPC CPU facility fitting >> for clockevents. In theory, FIT could be used -- but its period >> is measured in powers of 2, IIRC. > I'd really like to have that as an option. It would allow oprofile > to safely use hardware events on the MPC74xx "G4" processors. > Alternately it would allow thermal events. It is safe to use at > most one of the three (decrementer,profiling,thermal) interrupts. > If two were to hit at the same time, badness happens. Unfortunately, FIT exists only on Book E CPUs and MPC74xx aren't Book E, IIUC. > It's possible to wrapper the interrupt in something that divides > down, calling the normal code only some of the time. I think one > of the FIT choices is about 4 kHz on my system, which would be OK. Erm, are you sure you have FIT (or is your system not MPC74xx based)? > Full oprofile functionality would be wonderful. WBR, Sergei - 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/