Different CPU, same challenges
Nice to see, that i’m not the only one who thinks, that IBM will run in the same challenges like Sun in regard of massive multicore processors. Great to see, when this position is somewhat confirmed by someone who isn’t known as friendly to Sun and is said to be firmly on the blue side.
BlueToTheBone writes in his column “The Four Hundred” about Moore’s Law and the Performance Wall:
Well, with the Power7 chips coming next year, IBM has to get the multithreading fixed in DB2 for i or get a whole lot of excuses ready for why customers buy more cores and threads, running at lower clock speeds, and don't see performance go up.
But he points to an even more interesting point, that isn’t really a known territory to an open systems guy like me. Besides of this “bytecode-compiled is slower than iron-compiled” stuff (which isn’t true since the invention of Just-in-time-compilers) he has a very valid point. Much of the software is really old, and it wasn’t written for a environments with hundreds of cores. We learned the hard way, that there were a vast amount of pitfalls in the Open System world which thinks multithreaded/multiprocess for quite a time now. Now software developed in RPG and COBOL (and many code lines originate from a time when many of us weren’t even a glint in the eyes of our parents) hits with Power7 on an environment that doesn’t fulfill on the promise of ever-increasing single-thread performance. BlueToTheBone comes to a similar conclusion than the one i’ve made a while ago. Perhaps many applications stay on Power6 while newer developments can move to Power7:
. It might even mean putting off a move to Power7 iron and sticking with Power6 or Power6+ boxes as you dig through your code and see how parallelization can and cannot be used to make your applications run faster as well as offer more capacity to support more work.