Hello, I am looking to add an ability for hwloc to be able to access the system topology when operating in the control domain (dom0) of a Xen virtualisation environment.
At the moment, lstopo picks up the VM faked topology. To avoid OS schedulers attempting to be 'clever' with their topology, the faked topology is 1 socket per vcpu, to prevent a scheduler attempting to perform numa optimisation across cores which are not actually numa-adjacent. Being a Xen developer myself, I am more than happy with the aspect of getting the topology information from Xen. However, I have no idea how to integrate this into hwloc. I believe can make a topology-xen.c without too much trouble. It likely wants to checked before an os-specific hook (Xen dom0's come in at least Linux, FreeBSD, NetBSD flavours which have mainstream support) Are there any hints/suggestion/information about how to go about integrating this? What is the policy with regards to linking against new libraries by default (or perhaps by an --enable-xen configure option)? At the very least, it would need to link against libxenctrl.so which is a userspace library to issue hypercalls (abstracted away from the OS specific mechanism). Thanks, ~Andrew
