cpu0 and interrupts

Matthew Dillon dillon at apollo.backplane.com
Tue Jun 20 09:05:46 PDT 2006


:I see something about before that all interrupts run on
:cpu0 but I don't understand completely. If you have
:software interrupt in driver (a timer) does that also
:always run on cpu0? So there is no chance to separate timer
:processing?
:
:Dimitri

    The kernel SYSTIMER abstraction is per-cpu, but the current implementation
    uses the 8254 timer so the actual hardware interrupt goes to just one
    cpu.  IPI messaging is used to forward it to the correct cpu.

    On systems with APICs, there is a local apic timer for each cpu.  It
    would not be too hard to make the SYSTIMER abstraction use that timer
    to get per-cpu timer interrupts.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>





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