It can't (simdjson is fast compared to other text parsing - it's still extremely slow compared to native types), but that fact actually doesn't matter because t

It can't (simdjson is fast compared to other text parsing - it's still extremely slow compared to native types), but that fact actually doesn't matter because the problem isn't the parsing. Even the construction of these text files in proc is too slow. You can't read /proc/net/tcp within a reasonable amount of time on a system with hundreds of thousands of connections. Even allocating/churning memory to store a textual representation becomes a problematic overhead.