A 1 gigabyte no-IO dd is an unusual microbenchmark: it stresses only syscall rates while wasting time with memcpy. (A loop on getpid() or equivalent would have

A 1 gigabyte no-IO dd is an unusual microbenchmark: it stresses only syscall rates while wasting time with memcpy. (A loop on getpid() or equivalent would have worked just as well.) On my workstation the plain dd runs in 40 ms, with systemtap one-liner instrumenting/aggregating those 1 million write(2) syscalls in the kernel extended that tiny runtime to about 50 ms for a 1.25x slowdown. But such small numbers are hardly meaningful. I'm curious to what extent userspace perf script postprocessing is deemed a technological equivalent to this; or why a new kernel module was deemed necessary versus the perf_event_open(2) ring-buffer abi.