Messages in this thread | | | From | "Iram Shahzad" <> | Subject | hrtimer: about hres_active | Date | Mon, 10 May 2010 19:27:06 +0900 |
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Hi
I am trying to understand the purpose of "hres_active" of hrtimer and have the following question in this regard.
It seems "hres_active" indicates whether high resolution mode is active or not. But I am not clear about the idea behind it.
I see that hres_active is initialized to 0 here: hrtimer_init_hres
and set to 1 here: hrtimer_run_pending -> hrtimer_switch_to_hres
That means hrtimer becomes "active" at the 1st timer softirq and remains so forever. Is this understanding correct?
My original concern is as follows:
hrtimer_get_next_event returns KTIME_MAX when hrtimer is "active". So if the above understanding is correct, then after the 1st timer softirq it will always return KTIME_MAX. This means cpu_idle will never take the hrtimer event into account and will always base its decision on the next event of the timer wheel. Is this intended behaviour?
I would highly appreciate any information about this. Please CC me because I am not a member of this ML.
Best regards Iram
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