AM1808 high resolution timestamps

Hi Dirk,

Long back, I have tried the  below sample code to measure the time  and it worked.

Steps:

1. copy the below code into a test.c file

2. Build the code using the ARM tool chain ( I used Linaro )

   $ sudo /home/gcc-linaro-arm-linux-gnueabihf-4.7-2013.03-20130313_linux/bin/arm-linux-gnueabihf-gcc -o test.o test.c -lrt

3. copy this test.o into your target rootfilesystem's home directory.

4. Boot linux on target board ( I used K2H EVM )

5. Go to the home directory and run the test.o

( In the place of sleep() function you can insert your function )

#include <stdio.h>      /* for printf */

#include <stdint.h>     /* for uint64 definition */

#include <stdlib.h>     /* for exit() definition */

#include <time.h>       /* for clock_gettime */

#define BILLION 1000000000L

int localpid(void) {

       static int a[9] = { 0 };

       return a[0];

}

main(int argc, char **argv)

{

       uint64_t diff;

       struct timespec start, end;

       int i;

       /* measure monotonic time */

       clock_gettime(CLOCK_MONOTONIC, &start); /* mark start time */

       sleep(1);       /* do stuff */

       clock_gettime(CLOCK_MONOTONIC, &end);   /* mark the end time */

       diff = BILLION * (end.tv_sec - start.tv_sec) + end.tv_nsec - start.tv_nsec;

       printf("elapsed time = %llu nanoseconds\n", (long long unsigned int) diff);

       /* now re-do this and measure CPU time */

       /* the time spent sleeping will not count (but there is a bit of overhead */

       clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &start);        /* mark start time */

       sleep(1);       /* do your own stuff / code here*/

       clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &end);          /* mark the end time */

       diff = BILLION * (end.tv_sec - start.tv_sec) + end.tv_nsec - start.tv_nsec;

       printf("elapsed process CPU time = %llu nanoseconds\n", (long long unsigned int) diff);

       exit(0);

}