On 12/09/2013 11:26 PM, Preeti U Murthy wrote: >> > If the cpu stopped the interrupt during deep c-state and without >> > monitor/mwait support, which kind of ipi can wake the cpu? I mean like a >> > x86 cpu, APIC stopped in c3 mode, but actually ipi send via apic bus. So >> > I don't know which ipi work? >> > > As far as my understanding goes, an external interrupt sent via the apic > bus wakes up a core in deep idle state first,
Is there some evidence for this? Documents or some explanation? meaning powers on the core > and hence the local apic. It does not yet acknowledge the interrupt, > meaning it cannot invoke the interrupt handler immediately. > After the core goes through some initialization steps after wakeup, > it will be in a position to acknowledge the external interrupt and > service it accordingly. > > Ideally the interrupt handler of this external interrupt should be that > of the local timer itself since it was meant to act on the behalf of the > local timer interrupt. > Added more Intel experts. Many thanks for response, Preeti! But I still don't know how to get external/internal interrupt by a deep c-state cpu. In Intel Architecture Software Developer's Manual Vol.3A, Figure 10-3. Local APICs and I/O APIC When P6 Family Processors Are Used in Multiple-Processor Systems. The Local APIC is response for the the external/internal interrupt receiving. and It is included in CPU. And some explanation often be used in wikipedia. (http://www.hardwaresecrets.com/article/Everything-You-Need-to-Know-About-the-CPU-C-States-Power-Saving-Modes/611/4) It said the APIC clock was stopped in deep c-state, So I am wondering how can the nonfunctional LAPIC pass interrupt to CPU? And for monitor/mwait idle method, seems deep c-state cpu need to keep a eye on memory bus. So seems the memory controller in cpu package is impossible to get into sleep, right? -- Thanks Alex -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
