Argh, Stray interrupts 2006

Matthew Dillon dillon at apollo.backplane.com
Thu Jun 1 10:43:26 PDT 2006


    A flood of stray irq 7 messages is typically indicative of a BIOS 
    SMP configuration problem.  It usually means that the PIC is sending
    EXT interrupt acknowledgement requests to several cpus at once (or
    to one dual-core cpu), and the BIOS hasn't setup the hardware to
    properly direct the interrupts to just one cpu pin.

    What happens is that one cpu acks the interrupt and clears the pending
    bit, then the other cpu tries to ack the no longer pending interrupt
    and gets the stray interrupt vector.  The stray interrupt vector is
    typically an undocumented hardware vector number, usually 7 or 15.
    Hence stray irq 7's.

    If you are running dual-core cpu's you can try adding this option to
    work around the BIOS misconfiguration:

    options         CPU_AMD64X2_INTR_SPAM

    But it may not work on opterons.  The problem is most commonly on 
    systems with DUAL-CORE cpu's and BIOSes that don't quite configure
    them properly.

						-Matt





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