On 16.09.2013, at 22:29, Benjamin Herrenschmidt wrote:

> On Fri, 2013-09-06 at 13:22 +1000, Paul Mackerras wrote:
>> POWER7 and later IBM server processors have a register called the
>> Program Priority Register (PPR), which controls the priority of
>> each hardware CPU SMT thread, and affects how fast it runs compared
>> to other SMT threads.  This priority can be controlled by writing to
>> the PPR or by use of a set of instructions of the form or rN,rN,rN
>> which are otherwise no-ops but have been defined to set the priority
>> to particular levels.
>> 
>> This adds code to context switch the PPR when entering and exiting
>> guests and to make the PPR value accessible through the SET/GET_ONE_REG
>> interface.  When entering the guest, we set the PPR as late as
>> possible, because if we are setting a low thread priority it will
>> make the code run slowly from that point on.  Similarly, the
>> first-level interrupt handlers save the PPR value in the PACA very
>> early on, and set the thread priority to the medium level, so that
>> the interrupt handling code runs at a reasonable speed.
>> 
>> Signed-off-by: Paul Mackerras <[email protected]>
> 
> Acked-by: Benjamin Herrenschmidt <[email protected]>
> 
> Alex, can you take this via your tree ?

Yes, on the next respin :). Or is this one urgent?


Alex

--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to