Messages in this thread | | | Date | Tue, 10 Apr 2001 16:10:28 +0200 (CEST) | From | Mikulas Patocka <> | Subject | Re: No 100 HZ timer ! |
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> > Note that you call mod_timer also on each packet received - and in worst > > case (which may happen), you end up reprogramming the PIT on each packet. > > This just indicates that the interface needs to be richer -- i.e., > such as having a "lazy timer" that means: "wake me up when _at least_ > N ns have elapsed, but there's no hurry." If waking you up at N ns > is expensive, then the wakeup is delayed until something else > interesting happens. > > This is effectively what we have now anyway. Perhaps the > current add_timer() should be mapped to lazy timers.
BTW. Why we need to redesign timers at all? The cost of timer interrupt each 1/100 second is nearly zero (1000 instances on S/390 VM is not common case - it is not reasonable to degradate performance of timers because of this).
Timers more precise than 100HZ aren't probably needed - as MIN_RTO is 0.2s and MIN_DELACK is 0.04s, TCP would hardly benefit from them.
Mikulas
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