#include <stdio.h>

int main(int argc, char** argv)
{
        int i;
	int loop = atol(argv[1]);

        for (i = 0; i < loop; i++)
        {
                getpid();
        }
}

NATIF:

time ./getpid 10000000

real    0m7.920s
user    0m3.990s
sys     0m3.940s

UML with sysemu

real    3m55.052s
user    0m5.962s
sys     0m46.385s

real    3m56.964s
user    0m5.846s
sys     0m42.635s

real    3m54.179s
user    0m5.981s
sys     0m47.154s

UML w/o sysemu

real    6m16.956s
user    0m5.250s
sys     0m58.462s


real    6m17.126s
user    0m4.846s
sys     1m1.731s


real    6m16.461s
user    0m5.077s
sys     0m59.365s

---------------------------------------

original UML:

time make dep > /dev/null

real    4m51.669s
user    0m37.462s
sys     0m51.846s

time make bzImage modules > /dev/null

real    13m35.457s
user    4m18.885s
sys     1m40.481s

UML with sysemu:

time make dep > /dev/null

real    3m52.486s
user    0m37.981s
sys     0m50.808s

time make bzImage modules > /dev/null

real    13m5.980s
user    4m18.096s
sys     1m40.115s