Xen 4.2 will contain two new scheduling parameters for the credit1 scheduler which significantly increase its confurability and performance for cloud-based workloads:
ratelimit_us. This blog post describes what they do, and how to configure them for best performance.
Linux 2.6.37, released just few days ago, is the first upstream Linux kernel that can boot on Xen as Dom0… Just enabling CONFIG_XEN in the kernel config of a 2.6.37 Linux kernel allows the very same Linux kernel image to boot on native, on Xen as Dom0, on Xen as normal PV guest and on Xen as PV on HVM guest!
I’m working on now is an automated test framework, which will measure the effectivenes of the scheduler. This is actually a bit trickier than one might expect. You can’t simply run a workload by itself and measure its performance; for that use case, you don’t actually need a scheduler. You need to run each workload in competition with an array of other workloads, and at various levels of CPU “pressure”.