Just Czechin' In

Much to the delight of the boss, I made it to Prague Czech Republic where I've been emersed in multi-core/multi-threading (mc/mt) and Rohozec, Chodovar, and Pernstejn beer. Come on...I knew the boss would buy that bit about hanging out at coffeehouses and attending lectures, but you know me better than that. Purely educational research, of course.

Still, I did catch a couple of sessions on mc/mt. When it comes down to it, the key issues regarding mc/mt implementation as we move from the GHz era into the multi-core era are:

• Scalability
• Predictability/Determinism
• Maintainability

From what I can tell, no one of these issues is any more important than the other. Scalability, for instance, is critical as we move from multi- to many-core (the difference being from a processor that has, say 4 or 8 cores, versus one that has a whole bunch more). If you don't keep scalability in mind when writing multi-core apps, then you may have to do a lot of re-architecting and re-coding when you jump up to 40 or 60 or 80 cores on a processor. Of course, if the program you're writing doesn't do what you expect (i.e., predictability), then it doesn't matter how many cores it has. And finally, you (or more likely another developer) have to be able to understand the program enough to make changes when (not "if") required.

Here's something else I learned, maybe because I'd never given it any thought. The upcoming class of many-core processors will likely have cores of different sizes. Big cores for big jobs (database activity or server stuff), and little cores for quick-and-dirty jobs. Makes perfect sense, but like I said, I'd just never thought about it. Which is why, of course, I go to conferences like this in the first place.

What?!? You thought it was the beer?

-- Jonathan Erickson
jerickson@ddj.com

Posted by Jon Erickson at 06:01 PM  Permalink