Re: [Qemu-devel] [RFC 04/17] pseries: Make cpu_update during CAS unconditional

[Thomas Huth]

On 30.10.2016 12:11, David Gibson wrote:
> spapr_h_cas_compose_response() includes a cpu_update parameter which
> controls whether it includes updated information on the CPUs in the device
> tree fragment returned from the ibm,client-architecture-support (CAS) call.
> 
> Providing the updated information is essential when CAS has negotiated
> compatibility options which require different cpu information to be
> presented to the guest.  However, it should be safe to provide in other
> cases (it will just override the existing data in the device tree with
> identical data).  This simplifies the code by removing the parameter and
> always providing the cpu update information.

But updating the CPU device tree again and again will also increase the
QEMU start-up time... Considering that guest start up time is sometimes
also an issue, do you think that this code simplification really worth
the effort here?

 Thomas