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  1. changing the prioirty form inside the rt-class?

    Hi,

    If I add some scheduling logic inside the rt-class, in task_tick_rt(..) and if I from this function want to change the priority, higher or lower.

    As I do now I only change the...
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    priorities in Linux kernel??

    Hi, I noted that there are a lost of different priorities in the linux kernel.

    in the task structure we have:


    unsigned int rt_priority;
    and
    int prio, static_prio, normal_prio;

    What are...
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    Ok, thanks Mats, really helped a lot as usually....

    Ok, thanks Mats, really helped a lot as usually. :)
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    Ok, when I check my menuconfig I find the "timer...

    Ok, when I check my menuconfig I find the "timer frequenzy" set to 250HZ is this it? so every 4ms then?
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    Ok, thanks again. No-one that knows how long...

    Ok, thanks again.

    No-one that knows how long this tick-interrupt is? how often do task_tick_rt() get called? how to check?
  6. Hmm, but confusing with the naming rq->curr,...

    Hmm, but confusing with the naming rq->curr, sounds like thats the current task?


    And why isn't rt_priority used instead of prio?


    So p is the current task that is being preempted? But isn't...
  7. more kernel hacking, the check_preempt_curr_rt() func

    The following function in the linux kernel is a little confusing for me:



    /*
    * Preempt the current task with a newly woken task if needed:
    */
    static void check_preempt_curr_rt(struct rq...
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    Thanks for the answers. Of course you are...

    Thanks for the answers.

    Of course you are right about the tick func not being called every ns. But I'd want to get the time every tick. And for this you mean that TSC is better then sched_clock()?...
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    kernel hacking, plz help

    Hi, as a nob kernel hacker I want to capture in the rt-class the following events: task gets preempted, task gets blocked, task wakes up from being blocked, task tick. I got the following questions:...
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    thanks matsp, your code works perfect, thanks,...

    thanks matsp, your code works perfect, thanks, problem solved. :)
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    Ahh, ok thanks will try your code, must have been...

    Ahh, ok thanks will try your code, must have been writing my post same time as you did. just saw it.
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    Ok, thanks you for your answers, but I'm kind of...

    Ok, thanks you for your answers, but I'm kind of new on the memory management in C, so how do I increase the stack size? how do I allocate memory on the heap?

    Don't malloc use the heap? Are the...
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    Ahh, ok, but how to allocate memory the correct...

    Ahh, ok, but how to allocate memory the correct way then?
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    so how do I "allocating the memory through a...

    so how do I "allocating the memory through a pointer", thats what I'm trying to do in my second code section, what is wrong?
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    How to may a REALLY big array?

    Hi,

    I want to make a BIG array with about 10M elements, but it seems like I'm overflowing the stack, if I do an array of 500 000 elements its ok, but when I go to 5 000 000 I get segmentation...
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    clock cycle counter?

    Is there some function in c under linux that one can use to count clock cycles/nr of ticks? or similar? preferably in nano secs.
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    Lost in the kernel, sched.h?

    Hi, doing some kernel hacking but I'm a little lost ...

    I want to extend the sched_param structure in /include/sched.h. So that when I create threads with pthreads I can set these new parameters....
  18. d'oh! Found it: task_has_rt_policy(); .... ...

    d'oh!

    Found it: task_has_rt_policy(); ....

    Still question about jiffies remains.
  19. How do I determine if a task is i real-time task in schedule()?

    Hi, I'm currently working with a custom scheduler in linux kernel 2.6.23.9. Or actually I'm porting a scheduler I all ready made in Solaris, anyway in sched.c in the schedule() function, I need to...
  20. Ok, so when schedule() is called it puts this...

    Ok, so when schedule() is called it puts this task, the one that just got placed on the sleep queue, off the CPU and pick the next one to run, that is the one with the highest priority? So the I can...
  21. Ok, I assume that the schedule() function is the...

    Ok, I assume that the schedule() function is the one switching the tasks so all I need to do the is to check which state the current task is being set to after being switched? That is is task1(t1) is...
  22. Where do a task get "wakeuped", blocked, preempted?

    Hi,

    Where in the linux kernel do a task get:

    1. "wakeuped" - that is after a task being blocked and the resource it been waiting for gets free, the task gets woken up, where in the kernel code...
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    I know in solaris there is gethrtime(), is there...

    I know in solaris there is gethrtime(), is there something similar in linux?
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    Thanks, sound good, hmm, but I'm kind of new to...

    Thanks, sound good, hmm, but I'm kind of new to macros, how do I use that?

    like:


    #define rdtscll(val) \
    __asm__ __volatile__("rdtsc" : "=A" (val))

    long long test;
    long long diff;
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    Timing code in C?

    How do I account for time in C? I mean if I have 20 lines of code and I want to know how long time it takes to execute them in nano secs, how do I get this time?

    Thanks
    /Micke
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