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

[Ellis H. Wilson III]

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

-- 
Ellis H. Wilson III, Ph.D.
      www.ellisv3.com