Re: Short Vectors Versus Long Vectors

John Levine <johnl@taugh.com> schrieb:

According to Lawrence D'Oliveiro  <ldo@nz.invalid>:

On Wed, 24 Apr 2024 23:10:47 -0600, John Savard wrote:
>

One of the things that those supercomputers that _do_ include GPUs are
praised for is being energy-efficient.

>
That I never heard before. I heard it in relation to ARM CPUs, yes, GPUs,
no.

>
NVIDIA says their new Blackwell GPU takes 2000 watts, and is between
7x and 25x more power efficient than the current H100, but that's
still a heck of a lot of power. Data centers have had to come up with
higher capacity power and cooling when each rack can use 40 to 50KW.

GPUs are very energy efficient per theoretical peak performance of
calculations per second.  Said peak performance is extremely high,
hence the huge power requirements...

But programming for GPUs is _much_ harder than programming for
vector computers used to be.  Getting to 10% of theoretical peak
performance is quite impressive.  Getting above 50% requires
the right problem, good knowledge of the GPU internals (which NVIDIA
does not tend to share - don't they want to have people have good
performance on their cards? and lots of thought and _very_ clever
algorithms.

I mean, my entire house is wired for 24KW and usually runs at more
like 4KW including a heat pump that heats the house.

Good thing you're not living in Germany, your electricity bill
would be enormous...