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 -- Libvir-list mailing list Libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list