/proc/pid/arch_status Is Coming To Show Architecture-Specific Details Of A Given Task
When CONFIG_PROC_PID_ARCH_STATUS is enabled, there will be this new arch_status file to expose any extra architecture specific information for a given task. At this point, it's just exposing the elapsed time since last using AVX-512.
This is the evolution of the work talked about earlier this year for the Linux kernel better tracking AVX-512 usage in order to provide for more optimal task placement. That AVX-512 tracking code was merged back for Linux 5.1 while at the time it was going to be exposed to user-space via a status file, which didn't land initially and is now being exposed via this new arch_status concept.
This can provide guidance to a user/administrator (or more than likely, a script) whether a process ever used AVX-512 instructions and/or approximately the last time done so, such as if wanting to pin AVX-512 using (or not) processes to the same core(s).
The addition of the infrastructure and wiring in the AVX-512 reporting is in the x86/core tree ahead of next month's Linux 5.3 merge window.