CODEWITHSUNDEEP
clinux-kernel
Thudor
Thudor

Reputation: 349

Hrtimers and clockid_t problems

I am working on a new linux scheduler, and I need hrtimers. I read how to implement them, in: http://lwn.net/Articles/167897/

I made a small program, to test these timers before using them, and I have some problems.

That small program is something like this:

#include "linux/ktime.h"
#include "linux/hrtimer.h"
#include "linux/timer.h"
#include "linux/tick.h"

static void funcion_timers(unsigned long data) {

    printk(" HOLA HA SALTADO EL TIMER y el dato es %lu \n", data);

}

int main () {

    ktime_t kt;
    int i;
    struct hrtimer my_timer;
    clockid_t reloj;
    enum hrtimer_mode mode;
    kt = ktime_set(0, 5000000);
    reloj=CLOCK_MONOTONIC;
    mode=HRTIMER_REL;

    printk("EMPIEZA EL PROGRAMA");

    hrtimer_init(&my_timer, reloj);

    my_timer.function=&funcion_timers;
    my_timer.data=3;

    hrtimer_start(&my_timer, kt, mode);

    for (i=0; i<10000; i++) { } //A kind of waste of time cause I had problem with sleep into the kernel
}

And when I compile I am told (I'm not copying from the shell because it is in Spanish xD):

Why does hrtimer_init need arguments? I thought it was defined as:

*void hrtimer_init(struct hrtimer *timer, clockid_t which_clock);*

In conclusion, I think I may have not understand how clockid_t works; how does it work? I cannot find too much information about it on the Internet.

Thanks a lot, :D Alberto

Upvotes: 3

Views: 1706

Answers (2)

sonicwave
sonicwave

Reputation: 6102

As noted by Banthar, the API for hrtimers has changed, and thus made quite a few of the examples in existence on the internet outdated. You can have a look at the current functions at https://github.com/torvalds/linux/blob/master/include/linux/hrtimer.h, and the commit messages usually (cross your fingers first though) give an idea of what has changed, why, and what you should do to make your code work.

From the above link:

HRTIMER_REL has been renamed to HRTIMER_MODE_REL

hrtimer_init() needs a mode parameter (in your case probably HRTIMER_MODE_REL)

The callback function needs to be of type: enum hrtimer_restart (*function)(struct hrtimer *)

The data member has been removed from struct hrtimer, as the timer itself is now passed to the callback function.

Upvotes: 1

Kaz
Kaz

Reputation: 58637

int main()? Are you trying to call kernel functions from user space?

Upvotes: 2

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