ref: df7fcc6cac30738852965d9f4c1b6e90c6a977ae
dir: /sys/src/libc/9sys/cputime.c/
#include <u.h> #include <libc.h> #define HZ 1000 double cputime(void) { long t[4]; long times(long*); int i; times(t); for(i=1; i<4; i++) t[0] += t[i]; return t[0] / (double)HZ; }