Messages in this thread | | | Subject | x86 local timer interrupts getting lost | From | David Wragg <> | Date | 01 Dec 2000 01:30:31 +0000 |
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I've noticed that on dual processor machines, the two values in the LOC: line of /proc/interrupts are not in lockstep -- the difference between them varies. Using a perl script (below) to print out the difference every second, I see it wander around (by much more than the +/-1 error that /proc/interrupts involves). Sometimes the difference will jump, usually when the machine is under heavier interrupt load. I've seen jumps of more than 10, up and down on the same machine.
The machines I've been testing this on are a dual PPro and a dual Celeron, both running 2.4.0-test11.
Looking at the APIC documentation, it seems unlikely that the frequency of the local timer interrupts could be wandering differently on the two processors, so I suspect that the interrupts are actually getting lost. Does anyone know how this could be happening?
The perl script:
perl -e 'while(1) { open(IN, "</proc/interrupts") ; while (<IN>) { next unless /LOC:/; ($a, $b, $c) = split; } close(IN); print (($b - $c) . "\n"); sleep(1); }'
David Wragg - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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