Hello!

I've run into an issue with getcpu not having a vsdo implementation and taking anywhere from 600ns to 80us (avg 1 us) when using lttng-ust tracepoints. 

I am on lttng v2.13 and kernel version 4.9.253-l4t, running on a jetson (arm64). I was digging around and found that rseq might be the recommended next step

I am wondering:

1. Are there examples of using rseq system call to replace getcpu
   
2. Are there any existing patches that I can apply to get better getcpu performance