Parallella: A Supercomputer For Everyone • Hacker News Board

Re: Parallella: A Supercomputer For Everyone

#61

Post by DeepDuh » Wed, Oct 10, 2012, 4:48 PM UTC

adapteva wrote: post #57

DeepDuh wrote: post #33

Earlier quoted context omitted.

Ok, so that's 6.4 cores per mm^2 while Kepler has 4.8. Not bad, considering NVIDIA has already shrunk the scheduling ressources, register blocks and cache sizes per core to a bare minimum (something I don't agree with btw.).

What do you consider a Kepler core? The Epiphany cores are dual issue RISC processors that run independent C/C++ tasks.

Kepler has 8 "SMX" with 196 parallel sp threads each. For me the number of cores = the number of parallel threads, although on GPU they are not as independent, i.e. each "core" of an SMX either executes the same instruction on adjacent data or does nop. With dual issue do you mean a two stage pipeline or two threads in parallel, both performing FLOP?

Re: Parallella: A Supercomputer For Everyone

#62

Post by scott_s » Wed, Oct 10, 2012, 5:08 PM UTC

lotyrin wrote: post #56

scott_s wrote: post #55

Earlier quoted context omitted.

Sure, you're limited by money. But if someone magically was able to produce a machine for $100 that was on par with Titan ( http://en.wikipedia.org/wiki/Titan_(supercomputer) ) I would still call it a "supercomputer" until it became ubiquitous.

If they only had one, it doesn't matter how much it cost them to make, it's worth much much more than $100 dollars to someone. If there were enough supply that it were possible for it to be only $100 then it would have to already be ubiquitous. I agree with jacques_chester that it's an economic distinction.

Change "able to produce" with "willing to sell for" and my point remains the same.

I agree that you're not going to get a "supercomputer" for less than about $100,000. But supercomputers are defined by what they can do. Their cost is secondary. Necessary in a world without magic, but secondary. I can spend $100,000 on a computer, but that alone does not make it a "supercomputer".

Re: Parallella: A Supercomputer For Everyone

#63

Post by microtherion » Wed, Oct 10, 2012, 5:19 PM UTC

adapteva wrote: post #58

alexchamberlain wrote: post #17

Earlier quoted context omitted.

Very good way of summing it up!

Yes, agreed! We definitely got carried away with the marketing lingo and we apologize! This was our thought process: 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 joules YOUR application consumes on a specif…

As one of the HN contributors who mocked the GHz performance spec in an earlier discussion thread, I welcome the fact that you're engaging in debate about this.

That said, I still think that the GHz stat is just about as BAD a metric as any (I suppose "pin count times # of cores" would be worse :-). About the only positive inference I can draw from this is that you have the thermal situation in your system under control.

But piling up cores and cooling them is, IMHO, one of the easiest parts of designing a massively parallel system. The interesting part of the design is the interconnections between the cores, and any metric that multiplies single core performance by number of cores tells me nothing about that.

So not only am I not learning a key part of the performance characteristics of your system, but by omitting it, you make me wonder whether the ENGINEERING of the system might be similarly misguided on this aspect as the MARKETING seems to be (i.e. does marketing omit this aspect of the system because it was not important to the engineers either?).

Linpack at least has benchmarks both for showing off the cores in nearly independent scenarios, and for showing the system when actual communication has to take place. Obviously, each parallel application is different, but you'd at least show ONE indication of performance in situations that are not embarrassingly parallel (http://en.wikipedia.org/wiki/Embarrassingly_parallel).

Re: Parallella: A Supercomputer For Everyone

#64

Post by wtracy » Wed, Oct 10, 2012, 5:43 PM UTC

fuzzy wrote: post #41

sspiff wrote: post #8

Does anyone know what kind of cores these RISC cores will be? Will it be some lower end ARM version, or MIPS? Will it be something for which a wide array of tooling already exists, or will this have its own custom architecture which only works with their toolchain?

According to the kickstarter page the RISC cores are ARM A9.

There are two ARM A9 cores (running Ubuntu) and 16 custom Epiphany cores.

Re: Parallella: A Supercomputer For Everyone

#65

Post by fghh45sdfhr3 » Wed, Oct 10, 2012, 5:55 PM UTC

throwaway1979 wrote: post #25

I picked up a raspberry Pi a few days ago. Initially, I was blown away by the low price point. Since then, I've been reflecting on what makes a computer useful. For personal computers - desktops and laptops - I think we don't have a shortage of processor cycles. The minimal specs of the Raspberry Pi make it useable - 256MB of RAM, 700 MHz CPU, a few GB of storage and enough MB to saturate a home broadband connection.…

The raspberry Pi + tarsnap or dropbox is the disposable computer I've wanted for a while.

That plus cheap access to a massively parallel computer could also be very interesting.

Except where raspberry Pi + online storage could be useful to many, many people. Massive parallelism is probably only interesting to folks like us.

Re: Parallella: A Supercomputer For Everyone

#66

Post by sparky » Wed, Oct 10, 2012, 6:16 PM UTC

DeepDuh wrote: post #61

adapteva wrote: post #57

Earlier quoted context omitted.

What do you consider a Kepler core? The Epiphany cores are dual issue RISC processors that run independent C/C++ tasks.

Kepler has 8 "SMX" with 196 parallel sp threads each. For me the number of cores = the number of parallel threads, although on GPU they are not as independent, i.e. each "core" of an SMX either executes the same instruction on adjacent data or does nop. With dual issue do you mean a two stage pipeline or two threads in parallel, both performing FLOP?

"Dual issue" means "can issue two instructions per cycle", independent of pipeline depth or multithreading. In the case of the Epiphany, it can issue an ALU instruction and a floating point instruction each cycle.

Re: Parallella: A Supercomputer For Everyone

#67

Post by wtracy » Wed, Oct 10, 2012, 6:30 PM UTC

Since I thought I saw an Adapteva person posting here earlier:

If the Kickstarter falls through, what options could you still make available to hobbyists? Is there some version of your current prototype setup that you could sell, even if it's not one convenient board?

Re: Parallella: A Supercomputer For Everyone

#68

Post by wmf » Wed, Oct 10, 2012, 6:44 PM UTC

runako wrote: post #59

mchusma wrote: post #54

Earlier quoted context omitted.

I don't think a $2.35M round is really that much for a chip startup. The fact that they even think that they can plausibly launch a chip and some level of supporting documentation, software, etc for ~$3M total, that is a remarkably efficient use of funds. By the way, Kickstarter funds are "cheap" (no dilution & no debt) so anyone who can actually raise money on Kickstarter should do so.

I'm not qualified to evaluate how much money a modern chip startup needs to launch a product. But it's worth noting that the Kickstarter pitch doesn't mention the millions the company has raised so far (apologies if I missed that part). >> Kickstarter funds are "cheap" (no dilution & no debt) Of course they are, and that's kind of my point. Raising money from unsophisticated unaccredited investors without providing f…

They're not investors, they're donors.

Re: Parallella: A Supercomputer For Everyone

#69

Post by perlpimp » Wed, Oct 10, 2012, 6:54 PM UTC

is it me or erlang would sort of fit nicely into the core's ideology of data processing? Seems that LD is like set constant. there are external STR commands. You can have data loaded into registers from the code - MOV. Not an expert in Erlang but it seem that two ideologies can beneficial to one another.

And if it is so, should expecting Erlang compiler be out of the question? :)

Re: Parallella: A Supercomputer For Everyone

#70

Post by wmf » Wed, Oct 10, 2012, 7:03 PM UTC

unix-junkie wrote: post #45

What's the point in having such a RAM/core ratio? By assigning 4 threads per core (which is fairly common to exploit manycore architectures) you don't even have 4Meg of memory per thread. I would totally agree that memory constraint is sort of tied to manycore architectures, but in this case I find it pushed to the limits.

They don't have multithreading.