[Beowulf] Intel CPU design bug & security flaw - kernel fix imposes performance penalty

Joe Landman joe.landman at gmail.com
Wed Jan 3 09:57:48 PST 2018

Looks like it will respond to a 'nopti' boot option (at least the 
patches I've seen from 4-Dec)

On 01/03/2018 12:57 PM, Ellis H. Wilson III wrote:
> On 01/03/2018 12:47 PM, Lux, Jim (337K) wrote:
>> I suppose the down side is that if they do kernel mods to fix this
>> for the 99.9%, it adversely affects the performance for the 0.1%
>> (that is, us).
> We've been discussing this extensively at my workplace, and the 
> overwhelming expectation is that at least in Linux the fix should be 
> configurable such that those operating in non-multitenant systems 
> (such as scale-out storage appliances) can disable it.
> If this ends up not being the case, I would expect it in the 
> short-term to lock us out of upgrading to newer kernels where the fix 
> and resultant overheads come into play until we're on newer CPUs where 
> the architecture deficiency is resolved.  This latter part (the 
> expectation of Intel fixing it in their newer HW) is all the more 
> reason I'm inclined to believe the fix will be delivered as a tunable.
> Best,
> ellis

Joe Landman
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