A while back a client of mine was having sever performance issues with the newer, better Cisco UCS B230 M1 blade. Through troubleshooting we determined that their VMs were stalling due to the CPUs on the host entering an enhanced power state called C1E. I have confirmed that this behavior also exists with the B230 M2 Blade
Within the VMware vSphere performance best practices guide VMware recommends disabling the C1E power state in the server BIOS
Disable C1E halt state in the BIOS if multi-threadedp performance and I/O latency are important considerations. Consider enabling C1E if “Turbo Mode” is present and single-threaded performance of certain workloads is more relevant.
Cisco has now provided a way to disable the C1E power state as of the 1.4(3i) release
VMs on a blade running VMware hypervisor will be as efficient or fast as expected when compared to other blades using a different Intel architecture. The ability to disable the C1E state in the BIOS is now exposed and may need adjustment to correct the performance problem. (CSCtq00382)
However they have not yet provided a way to set this BIOS setting through the GUI or a policy within UCS manager so even after you upgrade to the 1.4(3i) or later software you will need to manually boot into the server’s BIOS setup and disable the C1E feature.
The default setting in the BIOS is enabled, you will need to manually change it to disabled until Cisco provides a way to disable it via policy