Re: [PATCH 1/6] x86-mce: Modify CMCI poll interval to adjust for small check_interval values.

From: Havard Skinnemoen
Date: Thu Jul 10 2014 - 13:17:04 EST


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.

Havard
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