From: Clemens Ladisch <clemens@ladisch.de>
To: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>,
Linux Kernel ML <linux-kernel@vger.kernel.org>,
robert.picco@hp.com, venkatesh.pallipadi@intel.com,
vojtech@suse.cz, mingo@redhat.com
Subject: Re: [Patch] Fix the possibility of insane return value of hpet_calibrate() against SMI.
Date: Mon, 16 Mar 2009 10:52:31 +0100 [thread overview]
Message-ID: <49BE215F.7040307@ladisch.de> (raw)
In-Reply-To: <20090316111300.7CE5.E1E9C6FF@jp.fujitsu.com>
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.
Could you, just for testing, run the calibration five thousand times or
so instead of five times, and count how often you get insane values?
(And how much delay does such an SMI add?)
> Each calibration of this has 1 milli second.
> Do you think 5 msec is too long?
This shouldn't matter when booting. Anyway, I think it's possible to
increase TICK_CALIBRATE without losing too much accuracy.
Best regards,
Clemens
next prev parent reply other threads:[~2009-03-16 9:57 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-13 5:00 [Patch] Fix the possibility of insane return value of hpet_calibrate() against SMI 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
2009-03-16 9:52 ` Clemens Ladisch [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=49BE215F.7040307@ladisch.de \
--to=clemens@ladisch.de \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=paul.gortmaker@windriver.com \
--cc=robert.picco@hp.com \
--cc=venkatesh.pallipadi@intel.com \
--cc=vojtech@suse.cz \
--cc=y-goto@jp.fujitsu.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.