For many months, perhaps years, we as programmers have realized our trouble ahead coming with the "manycore era". The attitude seems to be "someday we're really going to have to figure this concurrency thing out". But this month I have been hit with a terrible realization: the manycore era is already upon us. Technically, it's the "multicore", not "manycore", but I think that's a small distinction.
Why the sudden epiphany? A few weeks ago, I built my self a new computer and put in an Intel quad-core CPU. My computer is much faster now, and I'm very happy with it, but after a few weeks I have realized something: I never use more than 1/4 of my CPU. I have a little graph on my screen at all times showing me the CPU usage. It goes up to 25% all of the time, but I have never seen it go higher. Ever.
On one hand this is a good thing. The new computer is so fast that everything I do is instant, and only uses a tiny bit of power. If it isn't instant, it's usually disk or network bound, not CPU bound.
On the other hand, even my own software isn't using more than 25%, and it is CPU bound at times. I'd like to fix it, but it's written in python, and the short version of a long, boring story is that python has a thing called The GIL which makes it so python as currently implemented cannot use more than 25% of the CPU except under very rare circumstances.
It seems that programming languages takes a long time to be adopted, but I think concurrency is a big enough rule changer to shake up which programming languages are dominant. In my specific case, if python doesn't fix it's concurrency problems soon, I'm going to have to stop considering it because I'll never be able to get it to use more than 1 little piece of the CPU. Right now, that's 25%, but in a few years, it will be only 3%. Either python is going to have to change, or I'm going to have to change programming languages (or use something like Jython or IronPython, I suppose).
A few weeks ago, sitting behind my single core computer, I was in the "someday, we'll have to tackle concurrency" camp. Now, sitting in front of my quad core machine, never using more than 25% of its power, everything has changed. Concurrency is no longer a question of if or when, it's here right now. If you don't believe me, get yourself a quad-core machine and watch the CPU usage graph. I think you'll be surprised.