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Looking at the man page of /proc/stat the defination is irq - time servicing interrupts (since 2.6.0-test4); softirq - time servicing softirqs (since 2.6.0-test4). does irq = software irq + ...
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  1. #1
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    /proc/stat IRQ info what the number mean?


    Looking at the man page of /proc/stat

    the defination is
    irq - time servicing interrupts (since 2.6.0-test4); softirq - time servicing softirqs (since 2.6.0-test4).
    does irq = software irq + hardware irq? if so, the numbers don't seem look right. using the below thread info to compute the numbers
    CPU load high, top processes very low? - LinuxQuestions.org

    is irq = hardware irq?

    what does it mean? Anyone can explain?

  2. #2
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    On an embedded system (kernal 2.6.21), when I cat /proc/stat I noticed there are 10 columns on the CPU. I google around but I am unable to find info. What are these values? Are the last 2 in addition to the orginal 8 (kernal 2.6.11)?

    -------------
    cpu 16118 0 9479 654 0 282 6 0 0 2
    cpu0 16118 0 9479 654 0 282 6 0 0 2
    intr 170000 0 0 0 0 0 0 0 0 0 0 103 0 0 2289 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 26539 0 0 0 138381 186 0 0 2175 0 0 0 0 0 0 0 327 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
    ctxt 950940
    btime 10
    processes 616
    procs_running 3
    procs_blocked 0
    pi_init: 0
    nr_running(): 3
    nr_uninterruptible(): 0
    nr_uninterruptible(0): 0
    rt_nr_running(): 0
    rt_nr_running(0): 0
    nr_rt_uninterruptible(): 0
    nr_rt_uninterruptible(0): 0

  3. #3
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    see man 5 proc or proc. IRQ stands for interrupt request and AFAIK
    it covers both i.e. hardware and software.

    Regards,
    ndevel.

  4. #4
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    thanx for the reply. However in source kernel/sched.c seem to tell me irq covers Hardware IRQ, not both Hardware & Software.

    void account_system_time(struct task_struct *p, int hardirq_offset,
    cputime_t cputime)
    {
    struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
    struct rq *rq = this_rq();
    cputime64_t tmp;
    p->stime = cputime_add(p->stime, cputime);

    /* Add system time to cpustat. */
    tmp = cputime_to_cputime64(cputime);
    if (hardirq_count() - hardirq_offset)
    cpustat->irq = cputime64_add(cpustat->irq, tmp);
    else if (softirq_count())
    cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
    else if (p != rq->idle)
    cpustat->system = cputime64_add(cpustat->system, tmp);
    else if (atomic_read(&rq->nr_iowait) > 0)
    cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
    else
    cpustat->idle = cputime64_add(cpustat->idle, tmp);
    /* Account for system time used */
    acct_update_integrals(p);
    }

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