[libvirt] [V2]RFC for support cache tune in libvirt

Hi folks I’v send the V1 version RFC early this week, but no reply yet. Thanks Qiaowei for the comment, I’v change the RFC much more libvirt specify, please help to comments on. ##Propose Changes #Libvirtd configure changes Add a new configure option cache_allocation_ratio to libvirtd, which let libvirt to allocate how many cache to domains. Default is 0.5 Eg. On a host which has 55M cache, libvirt can allocate 55M * cache_allocation_ratio cache to domains ## Virsh command line changes: NAME cachetune - control or query domain cache allocation SYNOPSIS cachetune <domain> [--enabled true/false] [--type <type>][--size <number>] [--config] [--live] [--current] DESCRIPTION Allocate cache usage for domain. OPTIONS [--domain] <string> domain name, id or uuid --enabled <true/false> enable cache allocation --type <string> cache allocations type, support l3/l2 etc --size <number> the cache size in KB --config affect next boot --live affect running domain --current affect current domain This will allow libvirt to allocate specify type l3 cache for a domain Domain xml changes: <cachetune> <enabled=’yes’, size=4096, actual_size=4680,type=’l3’> <enabled=’no’, size=256, actual_size=0, type=’l2’> </cachetune> For more information about the detail design, please refer https://www.redhat.com/archives/libvir-list/2016-December/msg01011.html CAT intro: https://software.intel.com/en-us/articles/software-enabling-for-cache-all... Best Regards Eli Qiao(乔立勇）OpenStack Core team OTC Intel. --