[Qemu-devel] Intel Haswell : Cache monitoring technology and libvirt

[Qemu-devel] Intel Haswell : Cache monitoring technology and libvirt

[Jd]

Hi
We are looking to get processor level cache metrics for each running VM.
Does QEMU/KVM (or libvirt) set RMID for tagging processor cache metrics 
? How do I find RMID for a particular VM ?
(Once RMID is known, I am assuming we will be able to query the 
processor via MSRs to get values)
Any help / pointers will be appreciated.

Thanks
/Jd

Some more context :

https://01.org/blogs/skjain/2014/four-new-virtualization-technologies-latest-intel%C2%AE-xeon-are-you-ready-innovate

*Cache Monitoring Technology (CMT)* - allows flexible real time 
monitoring of the last level cache (LLC) occupancy on per core, per 
thread, per application or per VM basis. Read the raw value from the 
IA32_QM_CTR register, multiply by a factor given in the CPUID field 
CPUID.0xF.1:EBX to convert to bytes, and voila! This monitoring can be 
quite useful in detecting the cache hungry “noisy neighbors,” 
characterizing the quiet threads, profiling the workloads in 
multi-tenancy environments, advancing cache-aware scheduling and/or all 
of the above. Based on the CMT readings, schedulers can take subsequent 
intelligent actions to move and balance the loads to meet any service 
level agreement (SLA) in a policy driven manner. Intel® 64 and IA-32 
Architectures Software Developer’s Manual (SDM) volume-3 chapter-17.14 
provides the CMT programming details. CMT reference code is also 
available for evaluation under BSD license. For commercial use, please 
use the CMT cgroup and perf monitoring code being upstreamed for Linux, 
and both KVM and Xen.