Messages in this thread | | | Subject | Re: [PATCH] s390 (9/9): no timer interrupts in idle. | From | Martin Schwidefsky <> | Date | Thu, 22 Apr 2004 14:14:44 +0200 |
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> ok maybe I need to word it differently. > What I'm proposing as alternative is using the one shot mode of the timers > on most machines to do teh following: > when the timer irq hits, you do the business you need to do. And then you > check all existing timers and the scheduler when the next "virtual tick" is where > you're going to do real work. You then set the one-shot counter to that > amount. This means that in add_timer/mod_timer you will need to check if the > just added timer is before the current one-shot runs out, and if so, adjust > it. Perhaps in the scheduler too.
You can't do that with the current timer code. A HZ timer interrupt is used for several things: 1) increase jiffies_64, 2) update the xtime, 3) calculate the load every 5 seconds, 4) check cpu time limits and send SIGXCPU, 5) do interval timer stuff, 6) run local timer queue and 7) add time slice to current process. With your one-shot timer you won't do the correct updates to the jiffies and the xtime.
blue skies, Martin
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