Daniel P. Berrange a écrit :
TODO: These vcpus functions permits to dynamically change the vcpu/cpu relation after the domain has been started but nothing has been done regarding static cpus attribution in the XML configuration file of a domain.
Yes there is a few things left: - as you said the impact on XML format (I'm not sure how much should be extracted though)
Whether we need the vcpu mapping in the XML really depends on whether its useful to persist this stuff, or whether its something you can just define at runtime as required. VCPU mappings really get into the realm of runtime policy which I'm not convinced really wants/needs to be part of the basic XML document data.
For example, when talking in terms of policy I don't think you'd directly store info in terms of 'map vcpu-1 to host cpu 3'. Instead you'd probably want to express it as 'give domain X a dedicated fixed CPU', or 'let domain X share/float 3 cpus' with other domains. The policy/management app would then decide which particular VCPU<->Host CPU mappings to implement when starting up the domain. Such a decision would have to take into account existing VCPU pinning from other domains already running.
So really IMHO we don't need to rush into adding VCPU mapping to the XML. Better to wait and see if there are apps being created which explicitly need this info persisted in the XML.
Yes, I'm agree. It's better to wait and see the next Xen release with NUMA support and the new "Credit" scheduler because the cpu mapping policy depend narrowly on these features.