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SubjectRe: ia64 SN2 - migration costs: 1) nearly zero 2) BUG 3) repeated

* Paul Jackson <> wrote:

> I turned on migration_debug=3 at boot, enabled CONFIG_PREEMPT and some
> other CONFIG DEBUG options, and captured the output from the tty
> console instead of via the /var/log/messages file. This resulted in
> the following. Now I don't see the BUG, and the cost matrix makes
> more sense (not all 0's), and the matrix output is not repeated. I
> don't understand why. Feel free to ask me to try various
> combinations, Ingo, if this doesn't make sense to you either.

hm, these calibration results looks quite sane. Could you try
migration_debug=3 with the .config that failed before? (if it doesnt
fail, could you re-check it still fails with migration_debug=2?) Zero
results in the cost matrix usually are a sign of time resolution
problems - but that shouldnt be an issue on ia64 which should have a
globally synced TSC, right?

until these problems are solved, you should be able to work around it by
booting with the migration_cost=0,7512036,45850376 boot option.

you can work around the warning message via changing the:

int cpu1 = -1, cpu2 = -1, cpu, orig_cpu = smp_processor_id();

line to:

int cpu1 = -1, cpu2 = -1, cpu, orig_cpu = raw_smp_processor_id();

i'll do the correct fix.

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