But what kind of C program is he comparing against? Single threaded ones? Not heavily optimized ones? Optimized concurrent C programs that use locks rather than

But what kind of C program is he comparing against? Single threaded ones? Not heavily optimized ones? Optimized concurrent C programs that use locks rather than lock-free data structures? Or heavily optmized C programs with lock-free data structure? It is unclear to me. Also, wondering how much of that overhead in the C program is due to malloc (can be overcome by memory arena)