On Fri, Jun 07, 2013 at 11:06:09PM -0500, Mike Miller wrote: > What do you think of this?... > > http://www.geek.com/chips/a-99-linux-supercomputer-has-been-built-will-ship-this-summer-1552343/ > > All of those specs are fairly standard for a little $99 computer > nowadays, except along with the Parallela's ARM A9 processor, it > comes with a 64-core Epiphany Multicore Accelerator, which helps the > board achieve around 90 gigaflops. For comparison, that amount of > GFLOPS is equivalent to a 45GHz processor. Comparing apples and orangutans, again! Wikipedia page for Xeon [1] indicates that a Xeon X5365 (3.0 GHz, 8 MB of cache, 4 cores with Hyperthreading) performs to around 38 GFlops. And that is technology discontinued in 2009 [2] So, we need just 2.4 Xeons with 4 cores each at 3 GHz to get to 90 GFlops. or 2.4 Xeons with 1 core each at 12 GHz to get to 90 GFlops or 1 Xeons with 1 core each at 28.5 GHz to get to 90 GFlops Where are the other 27 GHz? Are they using an even older processor core? Secondly, one 45GHz processor is not equivalent with 45 1GHz processors. Even if the problem is fully parallelizable, there is still loss of performance due to the need to synchronize data stores, collision when accessing hardware resources such as caches, etc. But no problem is fully parallelizable, see "Amdahl's Law" [3]. Thirdly, "GFlops" are influenced not only by the speed of the CPU, but the bandwidth and latency of the CPU-memory interface. In order to crunch that much data, you have to get it in and out of the CPU. Looking at the diagram, it seems that the "supecomputer" shares the memory bus with all the peripherals, such as UART and USB. This is not how you design a supercomputer. The aforementioned Xeon has a 1333 MHz quad-pumped bus allowing transfers measured in tens of gigabytes per second. The power-optimized ARM bus is not running anywhere near that speed, and it would be like the bullet trains and Amish wagons (with Borg shields, so impervious to any collisions) sharing a couple of tracks. I wish I had such a massively multiprocessor system to play with, but this one isn't it. Cheers, florin 1: http://en.wikipedia.org/wiki/Xeon 2: http://ark.intel.com/products/30702/ 3: http://en.wikipedia.org/wiki/Amdahl%27s_law -- Sent from my last battery. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 198 bytes Desc: Digital signature URL: <http://mailman.mn-linux.org/pipermail/tclug-list/attachments/20130608/3d217297/attachment.pgp>