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Subjectunusual scheduling performance
On 16x, 2.5.47 kernel compiles take about 26s when the machine is
otherwise idle.

On 32x, 2.5.47 kernel compiles take about 48s when the machine is
otherwise idle.

When a single-threaded task consumes an entire cpu, kernel compiles
take 36s on 32s when the machine is idle aside from the task consuming
that cpu and the kernel compile itself.

I suspect the scheduler, because cpu reporting in top(1) shows that a
two or more cpu-intensive tasks are concentrated on the same cpu, and
some long-lived tasks appear to be "bouncing" across cpus. If someone
with knowledge and/or expertise with respect to scheduling semantics
could look into this, I would be much obliged. Resolving this would
likely address many SMP and/or NUMA scheduling performance issues.


Thanks,
Bill
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