Messages in this thread | | | Date | Sun, 4 Apr 1999 05:08:12 +0200 (MET DST) | From | Michel LESPINASSE <> | Subject | IO-APIC in non-SMP mode ? |
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Hi,
I am using a SMP board but I have only 1 CPU inserted. So I have an IO-APIC on-board but I am not running my kernel in SMP mode. Right now my kernel is not making use of the IO-APIC.
My understanding is that the IO-APIC allows to schedule interrupts to different processors (which I don't need), but is also a lot faster than the XT-PIC, thus allowing for much faster handling of interrupts. Is this correct ?
I tried manually inserting CONFIG_X86_IO_APIC=y and CONFIG_X86_LOCAL_APIC=y in my .config file and recompiling the kernel just to see if it boots, but this highly scientific approach must be flawed because it does not compile anyway :) To be more precise, compilation fails because FIX_IO_APIC_BASE is undefined, struct mpc_config_intsrc is undefined, boot_cpu_id is undefined and cpu_present_map is undefined.
Would there be any speed advantage to changing the SMP option to be YES, NO, or "Uniprocessor on SMP board" with this third option enabling the IO-APIC ?
-- Michel "Walken" LESPINASSE - Development Engineer at Wind River Systems walken@wrs.com - http://www.via.ecp.fr/~walken/ Microsoft has a Y2K problem. It's called Linux.
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