On Mon, Sep 05, 2005 at 09:57:30AM -0700, Nishanth Aravamudan wrote: > I think it's ok where it is. Currently, with x86, at least, you can have > an independent interrupt source and time source (not true for all archs, > of course, ppc64 being a good example, I think?) Perhaps "handler"
By "independent" do you mean driven by separate clocks? PPC64 does use decrementer as its interrupt source and Time-base-register as its timesource AFAIK. Both are driven by the same clock I think. > What may be useful is something similar to what John Stultz does in his > rework, attaching priorities to the various interrupt sources. For > example, on x86, if we have an HPET, then we should use it, if not, then > use APIC and PIT, but if the APIC doesn't exist in h/w, or is buggy > (perhaps determined via a calibration loop), then only use the PIT. This logic is what the arch-code should follow in picking its interrupt source and is independent of dyn-tick. dyn-tick just works with whatever arch-code has chosen as its interrupt source. > I agree. I guess max_skip, to me, is what the kernel thinks the > interrupt source should maximally skip by, not what the interrupt source > thinks it can do. So, I think it fits in fine with what you are saying > and with the code you have in the current patch. Great! > I was just wondering; I guess it makes sense, but did you check to see > if it ever *doesn't* get called? Like I said, __run_timers() [from how I Haven't tested that, but I feel can happen in practice, since we dont control device interrupts. > base->timer_jiffies) [the condition in run_timer_softirq()] is not. How > much does it cost to raise the softirq, if it is going to return > immediately from the callback? Don't know. It just felt nice to avoid any unnecessary invocations. -- Thanks and Regards, Srivatsa Vaddagiri, Linux Technology Center, IBM Software Labs, Bangalore, INDIA - 560017 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
