Messages in this thread | | | Date | Thu, 17 Dec 2009 14:34:24 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 2/2] x86/apic: check global clockevent in lapic timer setup |
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On 12/17/2009 02:31 PM, Pan, Jacob jun wrote: >> Wouldn't be better to operate the same way as in case of "noapictimer" >> boot option. I guess the non-pc x86 midplatforms you're mentioning >> do not use SMP ever but just to be consistent in code. >> > [[JPAN]] We do use SMP with hyper threading in Moorestown. > In that case we have a per cpu platform timer without global clockevent. > so i think we don't want the dummy lapic event. we don't want to use the > broadcast mechanism as mentioned in the comments before disabling lapic > timer. > > For moorestown, I can use x86_init.timers.setup_percpu_clockev > abstraction function so that Moorestown platform does not need to call > setup_boot_APIC_clock() if per cpu platform timer is used. so many IFs :). > > But in the case of having constant and always on LAPIC timer, we still do > not want the dummy lapic clockevent and the broadcast. we will just have > per cpu always on local apic timers without global clockevent device.
OK, I'm not entirely sure I follow this, and I'm not sure someone trying to understand the code in five years would, either. I don't really see the above translating into "we don't have a global clockevent, therefore we shouldn't initialize (but should still not disable) the local APIC timer."
-hpa
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