During its announcement of vSphere on April 21, 2009, VMware highlighted the tremendous performance enhancements in VMware vSphere. To illustrate this, VMware compared performance of an Oracle database workload running on
- Physical server with Intel Xeon 5100 Series dual-core processor
- VMware vSphere virtual machine hosted on a physical server with Intel Xeon 5500 Series quad-core processor with hyper-threading
The issue with this experiment is that it is impossible to evaluate the performance improvements of vSphere because not only was the original workload running on a physical machine, but it was also running on a machine with a different processor. Furthermore, the workload selected heavily leverages multi-core and hyper-threading technologies. So is performance improving because of enhancements to hardware or software?
To answer this question, the following experiments with different types of workloads should have been setup to measure
- Hardware Improvements: Physical machine with Intel Xeon 5100 Series processor versus a physical machine with Intel Xeon 5500 Series processor
- Hardware Improvements for Virtualization: VMware vSphere virtual machine on a host with Intel Xeon 5100 versus the same virtual machine on a host with Intel Xeon 5500 Series processor
- Software Improvements: VMware vSphere virtual machine versus a VMware Infrastructure virtual machine on identical underlying virtual machine hosts with Intel Xeon 5500 Series processor for each platform
Based on internal comparison of the two processors at Lanamark, the Intel Xeon 5500 Series is an order of magnitude superior compared to the Intel Xeon 5100 Series. It has four cores and up to eight threads versus only two cores without hyper-threading in Intel Xeon 5100 Series. Intel Xeon 5500 Series offers 6X-8X higher raw performance improvements in terms of operations per second. It also makes a huge leap forward in I/O processing thanks to
- Intel QuickPath Technology which provides speeds of up to 3.5X higher (25.6 GB/s) among processors and the I/O hub
- Intel Virtualization Technology for Connectivity (VT-c) which provides up to 2X throughput compared to non-hardware-assisted devices
- Intel Virtualization Technology for Directed I/O (VT-d) which eliminates a significant amount of virtualization overhead by giving virtual machines their own dedicated I/O devices
By taking a close look at the "substantial leaps in virtualization performance" announced by VMware, it is clear that these performance leaps are overwhelmingly driven by the hardware improvements highlighted above. Obviously VMware worked closely with Intel and vSphere takes advantage of the above hardware features. But if these hardware features enable the majority of virtualization performance improvements then Citrix XenServer, Microsoft Hyper-V and other virtualization platforms will reap similar benefits.