I need to run some HPC applications on the PV Guest (configured with multiple VCPUs and the application invokes also multiple processes to communicate with each other during the lifetime), and found that in some overcommitted cases, the application's performance degrades drastically. I got a Xen installation with both Dom0 and DomU running "vmlinuz-2.6.18.8-xen" kernel, i.e., the default configuration.

I am wondering if I can Upgrade the kernel of the PV Guest, i.e., domU, to run other alternative kernel, such as latest stable linux kernel, 2.6.28.8? By this way, it may be possible to avoid the performance sacrifice resulted by spin-lock problem.