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

[Jonathan Aquilina]

Chris on a number of articles I read they are saying AMD's are not
affected by this.

On 05/01/2018 17:27, Christopher Samuel wrote:
> On 05/01/18 10:48, Jörg Saßmannshausen wrote:
> 
>> What I would like to know is: how about compensation? For me that is
>> the same as the VW scandal last year. We, the users, have been
>> deceived.
> 
> I think you would be hard pressed to prove that, especially as it seems
> that pretty much every mainstream CPU is affected (Intel, AMD, ARM, Power).
> 
>> Specially if the 30% performance loss which have been mooted are not
>> special corner cases but are seen often in HPC. Some of the chemistry
>> code I am supporting relies on disc I/O, others on InfiniBand and
>> again other is running entirely in memory.
> 
> For RDMA based networks like IB I would suspect that the impact will be
> far less as the system calls to set things up will be impacted but that
> after that it should be less of an issue (as the whole idea of RDMA was
> to get the kernel out of the way as much as possible).
> 
> But of course we need real benchmarks to gauge that impact.
> 
> Separating out the impact of various updates will also be important,
> I've heard that the SLES upgrade to their microcode package includes
> disabling branch prediction on AMD k17 family CPUs for instance.
> 
> All the best,
> Chris

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