[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] [PATCH 2/4] CPUIDLE: Avoid remnant LAPIC timerintr while force hpetbroadcast
On Thursday, September 11, 2008 7:07 PM, Keir Fraser wrote: > On 11/9/08 11:59, "Tian, Kevin" <kevin.tian@xxxxxxxxx> wrote: > >>> Also, in your patch, you unmask LVTT after reprogramming the >>> LAPIC counter. >>> Isn't there a race where the LAPIC timer generates an >>> interrupt event before >>> you unmask the LVTT and hence you lose the interrupt (since I >>> assume the >>> LAPIC interrupt is basically an internal one-shot signal which >>> does not get >>> latched in any way)? So you'd probably need to reprogram_timer(0), then >>> enable the timer, then reprogram_timer(<actual value>). >>> >> >> You're correct. It will be fixed. > > Thanks. I'm not sure whether the reprogram_timer(0) before re-enabling is > really required. It looks like Linux doesn't do similar (although if course > it does re-programming after re-enabling to avoid the above race). > > I suppose repogram_timer(0) is cheap so you might choose to do it anyway. > It's up to you... Do reprogram_timer(0) anyway make things well controlled. So let's do it this way. Attached is the additional patch. Jimmy Attachment:
disable_apic_timer_in_c3_0911.patch _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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