Good, quick post over in Sun’s employee blogs (wonder if those will survive the acquisition) by Dan Templeton about topology-aware scheduling in the new Sun Grid Engine: what it is, why you might care, and a look at how to get started with it
It’s not just the powerhouse apps that care about CPU topology, though. Most operating systems will schedule processes and threads to execute on available cores rather willy-nilly, with no sense of core affinity. Because an average OS does context switches at a rather high frequency, an application may find itself executing on a different CPU and core every time it gets the chance to run. If that application makes any use of the CPU cache, for example, its performance will suffer for it. The performance might not suffer much, but the difference is usually measurable. For these reasons, we’ve added topology-aware scheduling to Sun Grid Engine 6.2 update 5.