[Beowulf] If I were specifying a new custer...

[Joe Landman]

On 10/12/2018 09:38 AM, Gerald Henriksen wrote:
> On Fri, 12 Oct 2018 09:24:18 +0100, you wrote:
>
>> I think the ARM/Cavium Thunder is going to see a lot of attention.
>> I saw a report recently from the Bristol/Cray Brunel cluster - they are
>> offering a range of chemistry codes and OpenFOAM,
>> compiled up for ARM.
>> Poke me and I will search for the report - I saw it on a twitter feed.
> ARM essentially has 2 problems.

I'd say 3, including what you wrote.

#3  End users are generally loathe to re-compile applications for a new 
processor/architecture, unless it gives them substantial benefit.  GPU 
rewrites were virtually guaranteed, once people got over the learning 
curve, as early (minimal) efforts yielded 5-10x performance bumps.  More 
work, and a rethinking of the application gave significant benefit.

ARM doesn't and as far as I can tell, won't have this advantage. The 
only advantage it brings potentially is power consumption per cycle.  
And this advantage evaporates once you start looking at the high 
computational power chips.

Recycling an old joke on this, ARM is the CPU of the future, and always 
will be.

Its not ABI compatible, ISA compatible.  Its not "blow the doors off" 
faster.  Its not (in the performance configurations) lower power.

Exactly what is the market draw of these processors?  What niche are 
they seeking to fill, and what unique advantages does it bring? These 
are not apparent.

Just my thoughts, but I've worked with some ARM product builders in the 
past, and have been burned by the misalignment between reality and rhetoric.


-- 
Joe Landman
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