AMD Zen4/Zen5 processors have been known to have slower entropy generation, which can lead to higher CPU utilization for workloads that depend on random number generation. I recently learned from a colleague (Ross Wynne) about a simple optimization for NSX Manager that can significantly reduce CPU utilization when running on AMD Zen4/Zen5 processors.
Shut down your NSX Manager VM and add the following VM Advanced Setting. This allows the guest operating system to retrieve entropy directly from the ESXi host, which already includes optimizations for entropy generation on AMD Zen4 and Zen5 processors.
isolation.tools.getEntropy.disable = FALSE
Note: Ensure you have applied the recommended entropySource configuration for your physical ESX host in addition to this configuration change.
In my limited testing, I have observed the NSX Manager load average drop to less than 5, whereas it was consistently much higher before applying this optimization. I will continue to monitor my environment, but this is definitely a worthwhile optimization to add to your VCF homelab toolkit. This configuration change can also benefit NSX Edge and NSX Virtual Network Appliances (VNA).
That's great, thanks!
Do you think this Ryzen Entropy optimization will also be beneficial for other CPU-heavy workloads, such as VCF Management Services Runtime or VCF automation?
Its not for general CPU-heavy workloads, but could benefit those that frequently request Entropy which can be slower on these AMD Ryzen processors. I haven't done further experiments to see if other appliances could benefit, since NSX Manager has been the larger consumer of the CPU (especially with reservations) but the other appliances have mostly been behaving at least for my setup.