ARM In Supercomputers — 'Get Ready For the Change' 238
An anonymous reader writes "Commodity ARM CPUs are poised to to replace x86 CPUs in modern supercomputers just as commodity x86 CPUs replaced vector CPUs in early supercomputers. An analysis by the EU Mountblanc Project (PDF) (using Nvidia Tegra 2/3, Samsung Exynos 5 & Intel Core i7 CPUs) highlights the suitability and energy efficiency of ARM-based solutions. They finish off by saying, 'Current limitations [are] due to target market condition — not real technological challenges. ... A whole set of ARM server chips is coming — solving most of the limitations identified.'"
IMHO - No thanks. (Score:2, Insightful)
PC user, hardcore gamer and programmer here; for me, energy efficiency is a lesser priority than speed in a CPU. Make an ARM CPU compete with an Intel Core i7 2600K, and show me it's overclockable with few issues, and you got my attention.
Re:IMHO - No thanks. (Score:5, Insightful)
No doubt your CPU would win. But when looking at power/price as well, you'd have to pit your CPU against 50 or so ARM chips in parallel. For some solutions, it may be a far better choice. One size doesn't fit all.
Re:Does it really matter? (Score:2, Insightful)
False. According to the Top 500 computer survey from November, 2012 (Category: Accelerator/Co-Processor), 87% of systems are not using any type of GPU co-processor, and 77% of the processing power is coming from the CPU.
This is, however, a decrease from the June 2012 survey, so GPU is certainly making inroads, but it is not yet the main source of computation.
http://www.top500.org/statistics/list/
I still remember when the IBM Blue architecture came out, using embedded PowerPC processors and it was a huge power savings. It was a big deal, but far from a complete solution (limitations in RAM with no disk/swap).
There is certainly a growing demand for a better power/performance solution in order to reduce total cost of operation. The individual performance of each processor doesn't matter as much when you have applications which are written to take advantage of 100,000s of processors in parallel.
That's what is so funny to me (Score:5, Insightful)
Slashdot seems to have lots of ARM fanboys that look at ARM's low power processors and assume that ARM could make processors on par with Intel chips but much more efficient. They seem to think Intel does things poorly, as though they don't spend billions on R&D.
Of course that would beg the question as to why ARM doesn't and the answer is they can't. The more features you blot on to a chip, the higher the clock speed, and so on, the more power it needs. So you want 64-bit? More power. Bigger memory controller? More power. Heavy hitting vector unit? More power. And so on.
There's no magic ju ju in ARM designs. They are low power designs, in both sense of the word. Now that's wonderful, we need that for cellphones. You can't be slogging around with a 100 watt chip in a phone or the like. However don't mistake that for meaning that they can keep that low consumption and offer performance equal to the 100 watt chip.
Re:IMHO - No thanks. (Score:5, Insightful)
For the record, I think addressing a bit more memory, and larger/faster storage channels are what's holding back some of these systems.. which aren't a problem at super-computer scale.. but for someone wanting to put together a small cluster, it gets irritating.
Re:Power Efficiency - MIPS vs ARM (Score:5, Insightful)
I may be wrong here, but I get the impression that the MIPS architecture is much more power efficient than that of the ARM architecture
If they are going to talk about building up a big iron using CPUs which are of high power efficiency, I reckon the MIPS cpu might be more suitable for this task than one from the ARM camp
I don't think it is. Best figures (albeit somewhat out-of-date) I can find for a MIPS-based system is 2GFLOPS/W for a complete 6-core node including memory. ARM Cortex A15 power consumption is a little hard to track down, although it's suggested that a 4-core 1.8GHz configuration (eg Samsung Exynos 5) could run at full speed on 8W (if the power manager let it; the Exynos 5 throttles down when it consumes more than 4W). Performance per GHz/core is about 4GFLOPS, so this system should be able to pull in about 28.8GFLOPS (or twice that if using ARM's "NEON" SIMD system to full advantage). Add in ~2W for 1GB DDR3 SDRAM, and that's 2.9GFLOPS/W. Assuming that the MIPS system I found is not the best available (as the data was from 2009 it certainly seems likely better is available now), the two appear to be roughly comparable.
Re:IMHO - No thanks. (Score:3, Insightful)
A single ARM 4 core A-15 running 1.5 GHz per core blows away any competing chip at the same specs, on power AND price. It's not limited to the calculations x86 are and can process graphics and physics better as a result.
Translation: It gets raped sideways on single-threaded performance and you have to double up on sockets right out of the gate.
It's a bit of a misconception about ARM and x86. ARM wins of watts/socket and mhz/watts, but Intel's i7s cream ARM on performance/watt, once you account for those two factors, ARM isn't as competitive as you might think. Now, I'm not saying it isn't competitive, just that it's nowhere near as one-sided as you might be led to believe by cherry-picking.