From: Vojtech Pavlik <vojtech@suse.cz>
To: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>,
clemens@ladisch.de,
Linux Kernel ML <linux-kernel@vger.kernel.org>,
robert.picco@hp.com, venkatesh.pallipadi@intel.com,
mingo@redhat.com
Subject: Re: [Patch] Fix the possibility of insane return value of hpet_calibrate() against SMI.
Date: Mon, 16 Mar 2009 09:59:09 +0100 [thread overview]
Message-ID: <20090316085909.GK5712@suse.cz> (raw)
In-Reply-To: <20090316111300.7CE5.E1E9C6FF@jp.fujitsu.com>
On Mon, Mar 16, 2009 at 11:34:55AM +0900, Yasunori Goto wrote:
> > I've no sense of feel for how long each calibration run would take.
> > Would doing it 5 times show up as a significant increase in the boot
> > time for those that care about boot time being as quick as possible?
>
> Hmm. The loop times is trade off against reliable value....
> Though SMI is rare interruption, I don't know how frequent
> hypervisor's switch is.
>
> Each calibration of this has 1 milli second.
> Do you think 5 msec is too long?
> If yes, how is 3 msec? Is it still too long?
I would suggest to instead repeat until the total cycle count stops
decreasing: That way we can avoid a SMI and yet in the best case only
run the calibration 2 times.
--
Vojtech Pavlik
Director SuSE Labs
next prev parent reply other threads:[~2009-03-16 12:14 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-13 5:00 Yasunori Goto
2009-03-14 8:23 ` Rik van Riel
2009-03-15 19:56 ` Paul Gortmaker
2009-03-16 2:34 ` Yasunori Goto
2009-03-16 8:59 ` Vojtech Pavlik [this message]
2009-03-16 9:52 ` Clemens Ladisch
2009-03-17 10:12 ` Yasunori Goto
2009-03-17 13:12 ` Paul Gortmaker
2009-03-18 0:45 ` Yasunori Goto
2009-03-18 2:47 ` [Patch] Fix the possibility of insane return value of hpet_calibrate() against SMI. (take 2) Yasunori Goto
2009-03-18 7:44 ` Clemens Ladisch
2009-03-18 8:25 ` Vojtech Pavlik
2009-03-18 13:55 ` Paul Gortmaker
2009-03-18 15:11 ` Clemens Ladisch
2009-03-18 15:32 ` Paul Gortmaker
2009-03-30 21:06 ` Andrew Morton
2009-03-30 21:23 ` Paul Gortmaker
-- strict thread matches above, loose matches on Subject: below --
2008-12-04 10:34 [Patch] Fix the possibility of insane return value of hpet_calibrate() against SMI Yasunori Goto
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