Re: [Lhns-devel] Re: Who's doing what with cpu/memory/node hotplug?

Matthias Fouquet-Lapar
2004-05-17T19:15:50Z

> Don't always equate HOTPLUG with physical removal/addition.
>
> In the above case of balancing between partitions, its a still a hotplug
> wrt the kernel, where the cpu is removed from os image (say scheduler etc)
> and reintroduce the new resource to another running partition.

Thanks, this make sense. I was previously working on systems which allowed
real physical hot swap, i.e. physical replacement of CPU, memory etc without
OS reboot, hence my questions.

[ Just as a site-note, I always wondered if hotplug would be a useful feature
for larger configurations to reduce boot-time. For example, on a 64P system
you start the kernel on some "root" CPU with a relativly small amount of
memory, so it should boot relativly fast. While the system is going into
the desired run-level, hotplug/add now adds in parallel all available CPUs,
main memory, I/O etc. The idea is that you probably don't need 64P and
1 Terabyte to start system services
]

Matthias Fouquet-Lapar Core Platform Software mfl@sgi.com VNET 521-8213
Principal Engineer Silicon Graphics Home Office (+33) 1 3047 4127