@kehoste The answer is basically 100%!
All supercomputers in the infamous Top500 list (@top500supercomp) are running a GNU/Linux distribution as operating system.
Check for yourself via https://t.co/QRukrO0Q5J (pick ‘Operating System" in Category).
#FOSS #HPC
^ @kehoste https://t.co/VMBm90KwHl