• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 98 subscribers
  • Views 805 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

AM335x precision time interval measurement using ordinary kernel functions

Sergio Kamakura
Expert 2495 points


Hi

I need to measure the total time for EDMA transfer  600Kbytes, from GPMC to a kernel buffer.

Which is the recommended method using ordinary functions available in kernel linux?

Which precision is possible? Milliseconds? Microseconds?

Examples available?

Sergio

  • 0
    TI__Guru 65405 points

    Hi Sergio,

    A possible way to measure time in Linux is by using clock() function. Example:

    #include <time.h>

    ......

    clock_t begin, end;
    begin = clock();

    // Your code

    end = clock();
    difference = (end-begin)/CLOCKS_PER_SECOND;

    The precision depends on the value of CLOCKS_PER_SECOND macro.



    BR
    Tsvetolin Shulev

  • 0 in reply to Cvetolin Shulev-XID
    TI__Guru 65405 points
    Sergio,

    One more time measurement way with precision in microseconds is using gettimeofday function. Sometimes in the worst case the real precision is tens microseconds.

    #include <sys/time.h>

    struct timeval start_time, end_time;

    gettimeofday(&start_time, 0);
    /*
    Your code should be here
    */
    gettimeofday(&end_time, 0);
    long elapsed = (end_time.tv_sec-start_time.tv_sec)*1000000 + end_time.tv_usec-start_time.tv_usec;

    elapsed value is measured in microseconds.

    BR
    Tsvetolin Shulev
  • 0 in reply to Cvetolin Shulev-XID
    Expert 2495 points
    Hi Tsvetolin Shulev

    Yes, the second method worked very fine for me. I can measure the time in microseconds resolution.

    Thanks a lot.

    Sergio