# The Exascale Computing Benchmark

# NetPIPE

Flops are irrelevant. Data matters, and data movement matters. Let's imagine
for a minute that we had a perfect quantum computing FPU that could execute
25 exaflops, took up 1 cubic millimeter, and used brownian motion to power
it. We'd have all the Exascale computing issues solved, and the chemists,
physicists, and climate modelers would start battling it out for time on
the machine, right?
Not so fast... To get a human the result of those 25 exaflops, we have to interact
with and observe the results. In a pretty much classical newtonian mechanics macro
-world in which as far as we can tell information transfer is accomplished with
discrete digital electrical or optical signals.

Well, if we take a step up out of CS theory, or maybe just go back to the turing
machine, we observe that those electrical and optical signals take energy in the
transmitter.. watts = current x voltage, and dissapate some of that heat in the
transmission media, and in the receiver. So really, the natural benchmark of our
exaflop quantum FPU is not in flops, but in bits/second. But if we are talking
about an exaflop in 1 cubic millimeter, we best be go find some mechanical engineers
who know practical stuff about thermodynamics and heat transfer, because the surface
of this cubic millimeter exaflop is going to be lit up like a quasar getting the data
in and out. But I don't need to go all sci-fi on you to prove a point.. The latest
processors from AMD and Intel modulate the CPU clock to stay within the thermal
envelope of the silicon package. Someone's going to bring up GPUs, but we have many
other practical problems getting data in and out of GPUs. And the fast ones run
really hot. I will bet you that the computing *system* that has the best
Bits/Joule is the one that will have the highest Bits/second (measured at the FPU),
and in in turn, the highest machoFLOPS.

So let's just forget the machoFLOPS, and evaluate the system on Bits per Joule for
effiency, and bits per second for peak capability... Hrrm.. What benchmark should
we use? Might I offer a suggestion? Or write a few
other ones. Or just report FLOPS in terms of bits/joule. Or exaflop/megawatt-hour
or something.

## Some interesting links on power densities

- 600kw/m^3
ITER fusion reactor
- 20kw/m^3 (200kw/20m^3) Toshiba Micro Nuclear
- approx 100Mw/m^3 in a nuclear reactor (784MWe * 3 = 2353MWheat / 2.5*2.5*3.7)
- approx 100Mw/m^3 in a 1cm x 1cm x 1mm active silicon dissapating 10 watts

The pig farmer with the highest density of computational chemistry knowledge I
have ever had the good fortune to work with. Thank you dirtbag.