This is the whitepaper I’ve been waiting for. By now we all know that the CPU Scheduler has changed. The only problem is that there wasn’t any official documentation about what changed and where we would benefit. Well this has changed. VMware just published a new whitepaper titled “The CPU Scheduler in VMware® ESX™ 4“.
The CPU scheduler in VMware ESX 4 is crucial to providing good performance in a consolidated environment. Since most modern processors are equipped with multiple cores per processor, systems with tens of cores running hundreds of virtual machines are common. In such a large system, allocating CPU resource efficiently and fairly is critical. In ESX 4, there are significant changes to the ESX CPU scheduler that improve performance and scalability. This paper describes these changes and their impact. This paper also provides details of the CPU scheduling algorithms in the ESX server.
I can elaborate all I want but I need you guys to read the whitepaper to understand why vSphere is performing a lot better than VI 3.5. (I will give you a hint: “cell”.)
Another whitepaper that’s definitely worth reading is “Virtual Machine Monitor Execution Modes: in VMware vSphere 4.0“.
The monitor is a thin layer that provides virtual x86 hardware to the overlying operating system. This paper contains VMware vSphere 4.0 default monitor modes chosen for many popular guests running modern x86 CPUs. While most workloads perform well under these default settings, a user may derive performance benefits by overriding the defaults. The paper examines situations where manual monitor mode configuration may be practical and provides two ways of changing the default monitor mode of the virtual machine in vSphere.
And while you arealready taking the time off to educate yourself you might also want to read the “FT Architecture and Performance” whitepaper. Definitely worth reading!