From: Andi Kleen <andi@firstfloor.org>
To: john stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>,
LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Clark Williams <williams@redhat.com>
Subject: Re: [PATCH] Greatly improve TSC calibration using a delayed workqueue
Date: Wed, 10 Nov 2010 14:47:01 +0100 [thread overview]
Message-ID: <20101110134700.GB7205@basil.fritz.box> (raw)
In-Reply-To: <1289338900.9434.51.camel@localhost.localdomain>
On Tue, Nov 09, 2010 at 01:41:40PM -0800, john stultz wrote:
> > It may happen with opportunistic suspend if the system boots very fast.
>
> Right, but a system using opportunistic suspend will have a hard enough
> time keeping close NTP sync on its own given the frequent switching
> between the fine-grained ntp adjusted clocksource during run-time and
> the coarse non-adjusted RTC/persisitent_clock while suspended.
>
> So I think such a system would be fine it falls back to using just the
> boot-calibration for TSC freq rather then the refined calibration freq
> calculated by this patch (which will happen automatically if the refined
> calibration is off by 1%).
>
> Does that seem like a reasonable tradeoff?
Yes it sounds good to me. Some inaccuracy in this case is fine I guess.
Just major inaccuracy or a crash or hang wouldn't be good.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2010-11-10 13:47 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-06 0:39 [PATCH] Greatly improve TSC calibration using a delayed workqueue John Stultz
2010-11-07 20:41 ` Andi Kleen
2010-11-08 22:04 ` john stultz
2010-11-09 13:43 ` Andi Kleen
2010-11-09 21:41 ` john stultz
2010-11-10 13:47 ` Andi Kleen [this message]
2010-12-05 11:18 ` [tip:x86/tsc] x86: Improve " tip-bot for John Stultz
2011-01-11 8:13 ` Kirill A. Shutemov
2011-01-11 8:26 ` Thomas Gleixner
2011-01-11 8:30 ` Kirill A. Shutemov
2011-01-11 8:37 ` Thomas Gleixner
2011-01-11 9:56 ` Kirill A. Shutemov
2011-01-11 10:26 ` Thomas Gleixner
2011-01-13 17:49 ` Konrad Rzeszutek Wilk
2011-01-13 18:01 ` john stultz
2011-01-13 21:40 ` [PATCH] acpi/pm: If failed at validating ACPI PM timer, inhibit future reads Konrad Rzeszutek Wilk
2011-01-13 22:15 ` Thomas Gleixner
2011-01-14 14:09 ` Konrad Rzeszutek Wilk
2011-01-14 15:44 ` john stultz
2011-01-14 15:54 ` john stultz
2011-01-14 16:02 ` Thomas Gleixner
2011-01-14 16:33 ` john stultz
2011-01-14 16:28 ` Konrad Rzeszutek Wilk
-- strict thread matches above, loose matches on Subject: below --
2010-11-10 21:51 [PATCH] Greatly improve TSC calibration using a delayed workqueue John Stultz
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