On Wed, 2007-06-06 at 14:25 +1000, Paul Mackerras wrote:

Jake Moilanen writes:

quoted

A Power6 can give up CPU cycles on a dedicated CPU (as opposed to a
shared CPU) to other shared processors if the administrator asks for it
(via the HMC).

This patch enables that to work properly on P6.

Is this something that needs to be controlled from userland, e.g. by a
sysctl or something in /sys?

The turning on of donating of dedicated CPU cycles is done via the HMC.
IHMO, it would be a bit redundant to do it in two places.

The reason why this is better than just shared processors is the
partitions w/ dedicated CPUs are guaranteed an actual processor, yet the
system is still able to increase the capacity of the shared CPU pool.

I have an updated patch come w/ a rename of the VPA field.

Jake