This is an alternative implemenation of: https://gist.github.com/vsivsi/fff8618ace4b02eb410dd8792779bf32
NOTE! This must be run on an Intel processor supporting AVX512F/DQ
Build and run (in background): gcc testmask.c testmask.s && ./a.out &
Send a bunch of SIGURG signals: for ((x=0;x<20;x++)); do kill -s URG <pid>; sleep 0.01; done