> From: Konrad Rzeszutek Wilk [mailto:konrad@xxxxxxxxxx] > Sent: Friday, December 23, 2011 11:01 AM > > > > OK. Lets put the # VCPU != PCPU aside. Say dom0 will boot with all > > > CPUs and then later on the admin starts unplugging them. > > > > This should be communicated to major Xen based distributions, so that it's > > an agreed approach since in majority case dom0 is configured as UP or > > a few VCPUs. > > I am not saying that is it the agreed approach. There has to be > flexibility in supporting both. But what I want to understand whether > the requirement for VCPU != PCPU can be put aside and put in the drivers > later on. sure. VCPU!=PCPU requirement is orthogonal to the basic part for gearing ACPI information to Xen. > > So that the first approach is not changing the generic drivers (much). > The reason I am asking about this is two-fold: > 1). For new distros (Ubuntu, Fedora), the default is all VCPUs. good to know that. > Enterprising users might use dom0_max_vcpus to limit the VCPU count, > but most won't. > Which mean we can concentrate on bringing the _Pxx/_Cxx parsing > up to the hypervisor. Which is really neccessary on any chipset > which has the notion of TurboBoost (otherwise the Xen scheduler > won't pick this up and won't engage this mode in certain > workloads). > 2). The ACPI maintainers are busy with ACPI 5.0. I don't know how > much work this is, but it probably means tons of stuff with > embedded platforms and tons of regression testing. So if there > is a patch that does not impact the generic code much (or any) > it will make their life easier. Which also means we can built > on top that for the VCPU != PCPU case. > > That is what I am trying to understand. no problem. this incremental approach should work. Thanks Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
