These syscalls are mostly through VDSO, so not very costly
The only VDSO-capable calls are clock_gettime, getcpu, getrandom, gettimeofday, and time. (Other architectures have some more, mostly related to signals and CPU cache flushing.)
The only VDSO-capable calls are clock_gettime, getcpu, getrandom, gettimeofday, and time. (Other architectures have some more, mostly related to signals and CPU cache flushing.)