On Wed, Jul 09, 2014 at 02:24:31PM -0700, Havard Skinnemoen wrote: > Date: Wed, 9 Jul 2014 14:24:31 -0700 > From: Havard Skinnemoen <[email protected]> > To: Borislav Petkov <[email protected]> > Cc: Tony Luck <[email protected]>, Linux Kernel > <[email protected]>, Ewout van Bekkum <[email protected]> > Subject: Re: [PATCH 1/6] x86-mce: Modify CMCI poll interval to adjust for > small check_interval values. > > On Wed, Jul 9, 2014 at 12:17 PM, Borislav Petkov <[email protected]> wrote: > > > > On Wed, Jul 09, 2014 at 10:09:21AM -0700, Havard Skinnemoen wrote: > > > From: Ewout van Bekkum <[email protected]> > > > > > > The CMCI poll interval was updated to pick the minimum interval between > > > the original 30 seconds and the check_interval divided by 8 (minimum of > > > 3 polls). > > > > 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.
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