Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269834AbUICUx5 (ORCPT ); Fri, 3 Sep 2004 16:53:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269820AbUICUx4 (ORCPT ); Fri, 3 Sep 2004 16:53:56 -0400 Received: from natsmtp00.rzone.de ([81.169.145.165]:22246 "EHLO natsmtp00.rzone.de") by vger.kernel.org with ESMTP id S269807AbUICUvX (ORCPT ); Fri, 3 Sep 2004 16:51:23 -0400 Date: Fri, 3 Sep 2004 22:26:15 +0200 From: Dominik Brodowski To: john stultz Cc: lkml , tim@physik3.uni-rostock.de, george anzinger , albert@users.sourceforge.net, Ulrich.Windl@rz.uni-regensburg.de, clameter@sgi.com, Len Brown , David Mosberger , Andi Kleen , paulus@samba.org, schwidefsky@de.ibm.com, jimix@us.ibm.com, keith maanthey , greg kh , Patricia Gaughen , Chris McDermott Subject: Re: [RFC] New Time of day proposal (updated 9/2/04) Message-ID: <20040903202615.GA18255@dominikbrodowski.de> Mail-Followup-To: Dominik Brodowski , john stultz , lkml , tim@physik3.uni-rostock.de, george anzinger , albert@users.sourceforge.net, Ulrich.Windl@rz.uni-regensburg.de, clameter@sgi.com, Len Brown , David Mosberger , Andi Kleen , paulus@samba.org, schwidefsky@de.ibm.com, jimix@us.ibm.com, keith maanthey , greg kh , Patricia Gaughen , Chris McDermott References: <1094159238.14662.318.camel@cog.beaverton.ibm.com> <20040903095435.GA11572@dominikbrodowski.de> <1094240482.14662.525.camel@cog.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1094240482.14662.525.camel@cog.beaverton.ibm.com> User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2132 Lines: 41 On Fri, Sep 03, 2004 at 12:41:22PM -0700, john stultz wrote: > > - cpufreq hooks to tsc.c and i386_tsc.c[*] can easily be added. For them to > > work _better_ than current code: can timeofday_hook() be called (with IRQs > > disabled) _anywhen_ from kernel context? > > [*] actually, only one of them needs the notifier, AFAICS... > > Yep, that's on my list. I'm trying to keep to just cleaning up one thing > at a time, but since I've got to re-work the timer_tsc.c code anyway, I > figured I'd try to organize all the TSC related functions > (synchronization, cpufreq, get_cycles(), tsc_delay maybe?) into tsc.c. > This will simplify things if we ever get around to correctly fixing the > SMP systems w/ different speed cpus issue. What about removing cpu_freq_khz you have in your patch, adding a per-CPU value, and just use the value of the boot CPU for the other CPUs if !CONFIG_DIFFERENT_CPU_SPEEDS or something like that? > > - what about keeping lower-priority timesources still "active" in some sort to > > a) enable loading _and_ unloading timsources (even modularizing them > > becoms possible which should make testing easier...), > > b) call them every couple of seconds to verify the currently used > > timesource is still sane (and if not, call cpufreq_delayed_get() for > > example or disable the timesource). This would mean that e.g. pmtmr > > and pit can be used to "verify" and "backup" tsc, or otherwise... > > The "clock=tsc" override would only affect the priority of the > > timesource then, making it so large that no other timesource can > > "preempt" it, but doesn't avoid making other timesources available > > for backup and verification purposes. > > That's totally the plan, although I want to put the control into sysfs. Even better. Thought about that too, but was worried you'd dislike the sysfs overhead. Thanks, Dominik - 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/