This still amazes me. A single Linux kernel image can be used for a 512 CPU machine. See SGI’s work here and the related SlashDot story. Sure you may have heard about Linux clusters with thousands of CPUs before. However, in most cases this was a cluster of machines with 1-4 processors each. The scalability requirements from the kernel side of things are very different when you are dealing with a few CPUs versus 512. You can find out more about the Altrix line at SGI‘s website.
Linux running the worlds fastest computer, wow!
What really fascinates me about this scalability work is the algorithms required. Making a system like this work efficiently isn’t about small optimizations it’s about having algorithms that can scale well.
One technique currently used in the Linux kernel is RCU. Linux journal has had couple of good articles on RCU which are available from their website.