• Jake Moilanen's avatar
    [POWERPC] Donate idle CPU cycles on dedicated partitions · d8c391a5
    Jake Moilanen authored
    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 enables that to work properly on P6.
    This just involves setting a bit in the CAS structure as well as the
    VPA.  To donate cycles, a CPU has to have all SMT threads idle and
    have the donate bit set in the VPA.  Then call H_CEDE.
    The reason why shared processors just aren't used is because dedicated
    CPUs are guaranteed an actual processor, yet the system is still able to
    increase the capacity of the shared CPU pool.
    Also rename the VPA's cpuctls_task_attrs field to a more accurate name.
    Signed-off-by: default avatarJake Moilanen <moilanen@austin.ibm.com>
    Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>