AM3874: Time resolution possible to achieve in Linux running on AM3874

Hello,

I would like to put my app to sleep for 100 microseconds. I've used usleep function but I've noticed that it sleeps for about 200 microseconds. I wrote the following program to check what's what:

#include <stdio.h>
#include <time.h>
#include <unistd.h>

int main(int argc, char **argv) {
    struct timespec res, tp1, tp2;


    clock_getres(CLOCK_MONOTONIC, &res);
    clock_gettime(CLOCK_MONOTONIC, &tp1);
    usleep(100);
    clock_gettime(CLOCK_MONOTONIC, &tp2);

    printf("resolution: %ld sec %ld ns\n", res.tv_sec, res.tv_nsec);
    printf("time1: %ld / %ld\n", tp1.tv_sec, tp1.tv_nsec);
    printf("time2: %ld / %ld\n", tp2.tv_sec, tp2.tv_nsec);
    printf("diff: %ld ns\n", (tp2.tv_sec - tp1.tv_sec) * 1000000000 + tp2.tv_nsec - tp1.tv_nsec);
}

The results are:

resolution: 0 sec 1 ns
time1: 136 / 905181953
time2: 136 / 905369318
187365 ns

So I get additional 87 microseconds. Is it possible to improve this and get as close to 100 us sleep as possible? Do I have to change something in my Linux configuration and recompile it?