On 09/29/2010 06:09 PM, Eric Blake wrote:
Here's where I ran out of time for the day. I'm much less familiar with xen than with qemu, so I have no idea how to tell if xen's documented domain/vcpu_avail (which is what we want for current vcpus) is usable in contrast to domain/vcpus (the maximum amount). For that matter, I'm not even sure if modifying the Sxpr parsing/generating code is enough to make xen use the new attribute, or what else might be involved. Hints on what I need to do from here are greatly appreciated.
--- src/xen/xend_internal.c | 6 ++++++ src/xen/xm_internal.c | 6 ++++++ src/xenapi/xenapi_utils.c | 2 +- 3 files changed, 13 insertions(+), 1 deletions(-)
Xen is more complex than I first thought. I'm debating whether to support xendConfigVersion <= 2 (xm_internal.h) or just xendConfigVersion >= 3 (xend_internal.h). Additional things I've discovered: http://lists.xensource.com/archives/html/xen-devel/2009-11/msg01061.html documents that the config file (xm_internal.h) has two parameters, vcpus is the max, and vcpu_avail is a bitmask of which vcpus to enable at boot. I'm assuming that xen cannot support more than 32 vcpus? http://www.cl.cam.ac.uk/research/srg/netos/xen/readmes/interface/interface.h... documents that each /domain sexpr contains vcpus (maximum), online_vcpus (current), and vcpu_avail (bitmask of online vcpus). The xm vcpu-set command can only change the current vcpus of a running domain, so I'm not sure how that interacts with persistent storage. I can't figure out whether I have to modify xm_internal.h to set the vcpu_avail bitmask to get this to happen, or whether changing the /domain sexpr also affects the persistent configuration. -- Eric Blake eblake@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org