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Parallella, a $99 Linux Supercomputer

zdnet.com

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Re: Parallella, a $99 Linux Supercomputer

#51

Post by jrockway »

amalag wrote: post #20
rys wrote: post #2

I find it incredibly dishonest of Adapteva to equate it to a "theoretical 45 GHz CPU". There are much better ways to talk about the performance level of their hardware than that metric, especially given the rest of the text in their Kickstarter pitch is aimed at people who need to inherently understand the hardware's execution model in order to program it effectively. The computing industry has established language a…

They do answer that on their kickstarter page: http://www.kickstarter.com/projects/adapteva/parallella-a-su... Why do you say the Parallella is a 45GHz computer? We have received a lot of negative feedback regarding this number so we want to explain the meaning and motivation. A single number can never characterize the performance of an architecture. The only thing that really matters is how many seconds and how many…

I read this as:

Why do you say the Parallella is a 45GHz computer?

This is a Kickstarter project. In order to be successful, we need to attract as much attention from spam blogs as possible. To do that, facts are not particularly useful. What we need is something exciting. If we say we have 64 cores, that's not exciting. 64? I've forgotten how to count that low. Similarly, if we say we have a 700MHz processor, most people listening to us talk will actually start laughing in our faces. So that's no good. But thanks to our mathematical forefathers, there are many ways to make small numbers big. We could add the two numbers, saying we have a 764MHz machine. But that's not exciting, and the units don't work. We could divide the two numbers, yielding 10.94MHz. The units work, but that number is even smaller! Finally, we could try multiplication! And, boy, does that deliver! 45GHz!

TLDR: The only reason you're here is because of our misleading and dishonest claim. But now you're here. Please cough up your hard-earned cash which we might not use to go on a nice tropical vacation. You can trust us, we'd never mislead you...

Re: Parallella, a $99 Linux Supercomputer

#52

Post by stephencanon »

helpbygrace wrote: post #28
Tuna-Fish wrote: post #11

Earlier quoted context omitted.

A single Ivy Bridge core has 8 Flops/MHz of computing power. 45GHz Ivy Bridge would be able to do 360GFlops.

If you are correct for the first clause(8 Flops/MHz), 45GHz of Ivy Bridge core has 360k Flops (8 Flops/MHz * 45GHz ==> 8 Flops * 45k).

8 double-precision flops/cycle/core is the correct figure for Ivy Bridge and Sandy Bridge. With Haswell adding FMA, that figure doubles again(!)

Re: Parallella, a $99 Linux Supercomputer

#53

Post by vidarh »

micheljansen wrote: post #43

Wow, I remember seeing the original Kickstarter for this and thinking "this will never see the light of day", yet here it is. I still find it a bit of an odd product; neither for hobby or business, but it sure is cheap.

It's a developer board. The product is the chips, not this board. This board is there mainly to get a dev board in the hands of people who might want to build cool stuff with it.

That they've actually managed to get it price competitive with a lot of cheap ARM computers, despite sporting a Zynq (ARM SoC with built in FPGA) is amazing.

Re: Parallella, a $99 Linux Supercomputer

#55

Post by vidarh »

yatsyk wrote: post #3

How many megahashes this hardware computes?

I love this board, but keep in mind that the entire premise of this board is parallel execution of _separate instruction streams_. From the performance people are getting from GPU's for bitcoin mining, I presume the calculations can be done extremely parallel with few instruction streams - for that a normal GPU is likely to be a far better choice.

Re: Parallella, a $99 Linux Supercomputer

#56

Post by Nursie »

lucb1e wrote: post #46
Leszek wrote: post #14

Earlier quoted context omitted.

Supercomputer =/= "a fast computer".

Then what is it? Wikipedia also seems to say it's "a fast computer": "a computer at the frontline of current processing capacity, particularly speed of calculation" https://en.wikipedia.org/wiki/Supercomputer

I've heard folks say before (and I include university profs in that) that it's a computer design focused on parallel calculation and low-latency I/O.

Not sure if this machine qualifies under that, but that is at least one competing definition to just "cutting edge and very fast"

Re: Parallella, a $99 Linux Supercomputer

#57

Post by rayiner »

swalsh wrote: post #34

There's so much negativity in this thread, wasn't the whole idea that these guys had plans and an architecture to scale up to the order of a terra-flop by 2014, and 20 by 2022? And look! they're shipping. This first chip may not be impressive, but I'll welcome a new player to the market who has big plans to innovate.

I don't get the negativity either. If you look at the architecture manual, this is like a cheap Tilera. It's an interesting programming model (lots of cores in a shared memory SMP with weak memory ordering), and the CPU's are pretty vanilla RISC architectures. For $99, it's a great way to play with something that has the properties of the kinds of CPU's you might see in a future supercomputer.

Re: Parallella, a $99 Linux Supercomputer

#59

Post by UnoriginalGuy »

vidarh wrote: post #48
trotsky wrote: post #18

Can anyone explain what the practical differences between something like this and a gpgpu approach? It doesn't sound particularly performant compared to modern gpus otherwise. Maybe they add in some more general purpose instructions for a little more flexibility?

A typical GPU can execute a small number of threads on a large number of streams of data carefully laid out in memory. Every time you want to do something conditionally on just one data stream, you waste a lot of capacity. In contrast, the Epiphany chips can execute individual threads on each core in parallel on data either local to the core (fastest), on any other core, or in separate main memory. The current Epipha…

This might be a really stupid question:

How difficult would it be in the practical sense to keep all of the cores on something like this "fed" with enough information to get benefits from its concurrency?

I mean to "feed" all 64 cores enough data/code so they can all "do something" concurrently is one hell of a job all on its own!

Re: Parallella, a $99 Linux Supercomputer

#60

Post by josephagoss »

jareds wrote: post #47
mkl wrote: post #39

Earlier quoted context omitted.

Each of the 64 cores can independently run arbitrary C/C++ code, which is much more flexible than a GPU. Each core has 32KB of local memory, which can also be accessed by the other cores, and there's 1GB of external memory too. Specs: http://www.adapteva.com/products/silicon-devices/e64g401/ Architecture: http://www.adapteva.com/wp-content/uploads/2012/10/epiphany_... SDK docs: http://www.adapteva.com/wp-content/uplo…

I wonder how much work it would take to port cpuminer to this platform for use in mining bitcoins and litecoins. Probably not worth it for bitcoins with the new FPGA hardware but could be interesting for litecoin depending on the memory access speed to main memory.

You mean the new ASIC hardware? The FPGA are ancient in the crazy world of Bitcoin, although a Litecoin FPGA will emerge in the next few month considering Litecoins value.
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