Hi, Daniel Daniel Veillard wrote:
I set the information of cpu_weight/cpu_cap to configuration file or sxp format, and execute "virsh start". But the information of weight/cap is lost. libvirt doesn't support cpu_weight and cpu_cap for XML format.
Right. To me cpu_weight and cpu_cap are tuning informations they are completely dependant: - on the hypervisor used (only Xen) - on a specific scheduler for said hypervisor - on the runtime operations conditions, i.e. you may want to revise those settings if you migrate the domain, or change anything on the target host
So you are suggesting to add this to the XML, while for me this makes little sense because of all this specificity. I have no doubt the patch would 'work' for you, but anybody using a different hypervisor, or different scheduler, or even someone trying to understand what those fields are would have no use or informations (your patch does not provide documentation for the meaning of those attributes).
I have a problem with extending the XML in a way which makes sense only for one hypervisor, when using a specific scheduler, and without a proper definition for what the extension actually means.
Yes, scheduler funtcion is xen specific. Other hypervisor(like qemu, kvm...) hasn't scheduer function. Threfore, extending weight/cap for the XML is meaningless for other hypervisor. The libvirt scheduler API is xen specific, it is necessary to add for XML's documentation that attributes weight/cap is effective only in xen.
Also Those informations are highly runtime dependant, it's tuning, it is not critical at all to get that tuning to get the domain up and running, and once it is running you can actually use the libvirt API to make the scheduler tuning.
Can you explain why you absolutely want to have that tuning information in the XML itself ?
In xentool case, weight/cap set by user to configuration file/sxp is seting at starting the domain. The user may not do anything. In libvirt case, the user should set weight/cap using libvirt api after starting the domain. I think that it is not convenient for the user. Thanks, Tatsuro Enokura