Shared memory in multi-processing is flawed
Gaberlunzie having learnt more from listening to David Manner's questions than he often did from the answers was intrigued by the mention of Hadrian's Wall in his blog pages, having lived near Antonine's wall, (mostly scavenged for building solid small castles, and sturdy farms) Having read the piece, Gberlunzie is reproducing the blog on multi-core processing ,with answers from 3L of Edinburgh and Sundance. It's so absolutely sane!
"The shared memory approach of Intel and AMD to general purpose multi-core processing is like building Hadrian’s Wall with 100 builders spread between Newcastle and Carlisle with one guy with a wheelbarrow delivering the bricks”, says Peter Robertson, MD of Edinburgh multi-processing company 3L.
The shared memory approach is a US route, whereas the Europeans take the different approach of spreading computing resources. “The US approach is to use shared resources, the European approach is separate resources”, says Robertson.
“There’s not a solution to the problem the way Intel and AMD are approaching it”, says Flemming Christensen, managing director of Sundance, “the whole concept of multi-processing using shared-memory is flawed.”
“They try to take a sequential language like C to capture parallelism", says Robertson, "people want to take code written for uniprocessors and magically turn it into something that will run on multiple processors and can be made to run as fast as you like just by throwing more processors at it. This is nonsense”, says Robinson.
“The Dual Core approach running on Windows is to have completely separate programmes running on different processors”, added Robertson, “it hasn’t solved the problem of getting one programme to run faster.”
“The approach of Flemming and I is that you have to recognise you need a vast number of processors, only some of which talk to eachother, and none of which talk to the whole system”, said Robertson, “and then you have to write the programme in such a way that the bits that need to talk to eachother, do talk to eachother You have to break the problems down, then you have a hope of distributing them across the processors.”
Will Intel and AMD ever get there?
“They’ll suddenly realise where they’ve been going wrong and take the right approach and then they’ll say they invented it”, replied Robertson, “I suspect Intel are doing it already, they’re just too embarrassed to admit it.”
Source: http://www.electronicsweekly.com/blogs/david-manners-semiconductor-blog/
Blog page: http://tinyurl.com/67sy3j