CPU-based I/O virtualization is common in high end microcontrollers. It typically supports PCI Express-based SR-IOV (Single Root I/O Virtualization) technology but this requires compatible peripheral controllers. Ethernet and storage controllers are often the focus of SR-IOV support found in servers.
AMD's new FirePro MxGPU series delivers virtualized GPUs for a range of applications including virtual desktop infrastructure (VDI) support. The FirePro S7150 and FirePro S7150x2 (Fig. 1) are typical of VDI solutions in that they have no physical display output ports. All physical display chores are done by a remote, network attached device. All computing, including GPU support, is done on the server.
AMD's solution is passively cooled with a TDP under 300 W. The S7150 is rated at 150 W while the S7150 x2 is rated at 265 W. They include out-of-band temperature monitoring support necessary for servers that may include multiple boards.
A server can handle up to 16 VDI clients per GPU (Fig. 2). The server runs a virtual machine (VM) per user. Each VM maps to a logical GPU managed by the hypervisor like VMware ESXi that in turn uses SR-IOV support to utilize part of the physical GPU resources. Driver support for is included for VMware vDGA, Citrix XenApp, Microsoft RemoteFX, and MxGPU.
The S7150 incorporates 2048 stream processors and 8 Gbytes of DDR5 memory. The boards do not support CrossFire, which links multiple boards to combine GPU power, but this is typically used in gaming systems where a single user is trying to get as much performance as possible. The VDI environment is more about sharing resources. The boards use a “fair time slicing” approach to providing GPU support.
Unlike software virtualized GPU interfaces, the FirePro provides hardware support for OpenCL on the virtualized GPU. VMs also use native AMD drivers that support OpenGL, DirectX, and OpenCL.
It is possible to adjust the amount of graphic performance delivered by the FirePro boards to a user by limiting the number of users per board. It is possible to support a mix of users on a single server and a server can support more than one FirePro board. A typical single board solution will handle 2-6 designers or engineers, 6-10 power users, or 16 average users.
The performance of the server's CPUs and the PCI Express fabric tend to be the limiting factors. Of course, the network interface is the entry point for a user's VDI link so having a cluster of CPU/FirePro nodes provides a scalable environment that is now limited by the performance of the network switches.
The FirePro targets VDI applications but it can be very useful for embedded applications that require a high degree of security or application isolation. They have also proven useful in high performance computing (HPC) applications, although the S91xx family usually targets this space.
The FirePro S7150 is priced at $2,399. The S7150 x2 is priced at $3,999.