Re: [PATCH 1/6] x86-mce: Modify CMCI poll interval to adjust for small check_interval values.
From: Chen, Gong
Date: Thu Jul 10 2014 - 22:42:36 EST
On Thu, Jul 10, 2014 at 10:16:56AM -0700, Havard Skinnemoen wrote:
> Date: Thu, 10 Jul 2014 10:16:56 -0700
> From: Havard Skinnemoen <hskinnemoen@xxxxxxxxxx>
> To: "Chen, Gong" <gong.chen@xxxxxxxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>, Tony Luck <tony.luck@xxxxxxxxx>, Linux
> Kernel <linux-kernel@xxxxxxxxxxxxxxx>, Ewout van Bekkum <ewout@xxxxxxxxxx>
> Subject: Re: [PATCH 1/6] x86-mce: Modify CMCI poll interval to adjust for
> small check_interval values.
> On Thu, Jul 10, 2014 at 2:01 AM, Chen, Gong <gong.chen@xxxxxxxxxxxxxxx> wrote:
> > On Wed, Jul 09, 2014 at 02:24:31PM -0700, Havard Skinnemoen wrote:
> >> On Wed, Jul 9, 2014 at 12:17 PM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> >> > Why min 3 polls? How do you come up with exactly that frequency?
> >> The idea is that if we make it equal to check_interval, it might
> >> bounce back and forth a lot. So we need to divide by something, and 8
> >> seems like a nice, safe value, and it seems to work well. We're not
> >> opposed to considering other values, of course (e.g. 2 and 4 might
> >> work well too, but with somewhat higher risk of ping-ponging).
> > That value looks chosen a little bit at will. How about updating
> > CMCI_POLL_INTERVAL when check_interval is changed to ensure
> > CMCI_POLL_INTERVAL <= check_interval always.
> I guess that would work equally well, but we still need to determine
> the magic number of how much less we want CMCI_POLL_INTERVAL to be.
I mean you can change CMCI_POLL_INTERVAL from a macro to a variable and
then do prove check.
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