Can you elaborate? What type of I/O, network, disk? What is the issue exactly?

You can refer to gvisor performance docs - https://gvisor.dev/docs/architecture_guide/performance/#file... throughput is really terrible, same deal with networking and also if your userland issues a lot of syscalls

Thanks for the link. I'm curious, how is the I/O performance with Kata? Does it use VirtIO?

It does and I believe with dax (if your kernel has it) it’s basically same speed as regular runc. 9p is still default tho i think