Zack's Kernel News
Zack's Kernel News

Chronicler Zack Brown reports on the latest news, views, dilemmas, and developments within the Linux kernel community.
cpusets, isolcpus, cgroups, Oh My!
Christopher Lameter wanted to restrict new process threads to just a subset of the CPUs installed on a system. This approach would allow real-time software to monopolize certain CPUs and, thus, guarantee their low latency requirements. He posted a patch to implement this at a very early stage of the boot cycle, so that the init process wouldn't start up user daemons on the wrong CPUs.
Gilad Ben-Yossef was very excited about this, but he didn't like the sheer number of parameters that users needed to set in order to use the feature. He suggested that folding Christopher's feature into the existing isolcpus feature might make this simpler. The isolcpus is a mechanism for removing specified CPUs from the scheduler's awareness and letting them run in isolation.
But, as Mike Galbraith pointed out, the isolcpus feature was going to be taken out of the kernel at some point in favor of the existing cpusets feature. Like isolcpus, cpusets lets the user hew off sets of CPUs (and associated regions of memory), so they can run in isolation from the rest of the system.
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