4.8. Virtualization

Performance monitoring in KVM guests, BZ#645365
KVM can now virtualize a performance monitoring unit (vPMU) to allow virtual machines to use performance monitoring. Note that the -cpu flag must be set when using this feature.
With this feature, Red Hat virtualization customers running Red Hat Enterprise Linux 6 guests can use the CPU's PMU counter while using the performance tool for profiling. The virtual performance monitoring unit feature allows virtual machine users to identify sources of performance problems in their guests, thereby improving the ability to profile a KVM guest from the host.
This feature is a Technology Preview in Red Hat Enterprise Linux 6.4.
Package: kernel-2.6.32-358
Dynamic virtual CPU allocation
KVM now supports dynamic virtual CPU allocation, also called vCPU hot plug, to dynamically manage capacity and react to unexpected load increases on their platforms during off-peak hours.
The virtual CPU hot-plugging feature gives system administrators the ability to dynamically adjust CPU resources in a guest. Because a guest no longer has to be taken offline to adjust the CPU resources, the availability of the guest is increased.
This feature is a Technology Preview in Red Hat Enterprise Linux 6.4. Currently, only the vCPU hot-add functionality works. The vCPU hot-unplug feature is not yet implemented.
Package: qemu-kvm-0.12.1.2-2.355
System monitoring via SNMP, BZ#642556
This feature provides KVM support for stable technology that is already used in data center with bare metal systems. SNMP is the standard for monitoring and is extremely well understood as well as computationally efficient. System monitoring via SNMP in Red Hat Enterprise Linux 6 allows the KVM hosts to send SNMP traps on events so that hypervisor events can be communicated to the user via standard SNMP protocol. This feature is provided through the addition of a new package: libvirt-snmp. This feature is a Technology Preview.
Package: libvirt-snmp-0.0.2-3
Wire speed requirement in KVM network drivers
Virtualization and cloud products that run networking work loads need to run wire speeds. Up until Red Hat Enterprise Linux 6.1, the only way to reach wire speed on a 10 GB Ethernet NIC with a lower CPU utilization was to use PCI device assignment (passthrough), which limits other features like memory overcommit and guest migration
The macvtap/vhost zero-copy capabilities allow the user to use those features when high performance is required. This feature improves performance for any Red Hat Enterprise Linux 6.x guest in the VEPA use case. This feature is introduced as a Technology Preview.
Package: qemu-kvm-0.12.1.2-2.355