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

[Peter Kjellström]

On Wed, 3 Jan 2018 17:47:42 +0000
"Lux, Jim (337K)" <james.p.lux at jpl.nasa.gov> wrote:

> I should think that in a "dedicated cluster" application, these sorts
> of security problems are less of an issue

Well I sure don't like the idea of random_flow_app.x reading our
slurm/munge secrets for latter convenient usage of resources, or root
equiv access to remote filesystem resources after reading out the
relevant bits, or the consequences of anyone being able to get at the
ssh host keys, etc. etc.

It sure sounds as patch and suffer the slow down for most forms of HPC
center I interact with.

As for the being able to turn (the meltdown) patch off I think there's
even a runtime sysctl option (at least in the redhat patch). And this
one isn't needed at all for AMD.

Seems slow down isn't too bad on codes nearer to HPC interestest such
as speccpu and hpl (from initial sources). I've seen 0-3% mentioned but
that was afaict not for multinode cases, that is, it remains to be seen
how high performace networking is affected (and thereby scaling).

/Peter
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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