Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752087AbZG3WEw (ORCPT ); Thu, 30 Jul 2009 18:04:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751828AbZG3WEv (ORCPT ); Thu, 30 Jul 2009 18:04:51 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:38352 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751704AbZG3WEv (ORCPT ); Thu, 30 Jul 2009 18:04:51 -0400 Subject: Re: [RFC][patch 10/12] move NTP adjusted clock multiplier to struct timekeeper From: john stultz To: Martin Schwidefsky Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Thomas Gleixner , Daniel Walker In-Reply-To: <20090729134231.515027738@de.ibm.com> References: <20090729134125.313191633@de.ibm.com> <20090729134231.515027738@de.ibm.com> Content-Type: text/plain Date: Thu, 30 Jul 2009 15:04:48 -0700 Message-Id: <1248991488.3374.14.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2913 Lines: 69 On Wed, 2009-07-29 at 15:41 +0200, Martin Schwidefsky wrote: > plain text document attachment (timekeeper-mult.diff) > From: Martin Schwidefsky > > The clocksource structure has two multipliers, the unmodified multiplier > clock->mult_orig and the NTP corrected multiplier clock->mult. The NTP > multiplier is misplaced in the struct clocksource, this is private > information of the timekeeping code. Add the mult field to the struct > timekeeper to contain the NTP corrected value, keep the unmodifed > multiplier in clock->mult and remove clock->mult_orig. For consistency > add the shift value associated with the NTP corrected mult value to > struct timekeeper as well. > > Cc: Ingo Molnar > Cc: Thomas Gleixner > Cc: john stultz > Cc: Daniel Walker > Signed-off-by: Martin Schwidefsky > --- > arch/arm/plat-omap/common.c | 2 +- > include/linux/clocksource.h | 4 +--- > kernel/time/timekeeping.c | 43 +++++++++++++++++++++++++------------------ > 3 files changed, 27 insertions(+), 22 deletions(-) > > Index: linux-2.6/include/linux/clocksource.h > =================================================================== > --- linux-2.6.orig/include/linux/clocksource.h > +++ linux-2.6/include/linux/clocksource.h > @@ -149,8 +149,7 @@ extern u64 timecounter_cyc2time(struct t > * @disable: optional function to disable the clocksource > * @mask: bitmask for two's complement > * subtraction of non 64 bit counters > - * @mult: cycle to nanosecond multiplier (adjusted by NTP) > - * @mult_orig: cycle to nanosecond multiplier (unadjusted by NTP) > + * @mult: cycle to nanosecond multiplier > * @shift: cycle to nanosecond divisor (power of two) > * @flags: flags describing special properties > * @vread: vsyscall based read > @@ -168,7 +167,6 @@ struct clocksource { > void (*disable)(struct clocksource *cs); > cycle_t mask; > u32 mult; > - u32 mult_orig; > u32 shift; > unsigned long flags; > cycle_t (*vread)(void); > Index: linux-2.6/kernel/time/timekeeping.c > =================================================================== > --- linux-2.6.orig/kernel/time/timekeeping.c > +++ linux-2.6/kernel/time/timekeeping.c > @@ -29,6 +29,8 @@ struct timekeeper { > s64 ntp_error; > int xtime_shift; > int ntp_error_shift; > + u32 mult; /* NTP adjusted clock multiplier */ > + u32 shift; /* NTP adjusted clock shift */ I'm a little confused here. NTP doesn't adjust the shift value. This seems redundant with the xtime_shift value introduced in [patch 9/12]. thanks -john -- 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/