time accounting problem (powerpc only?)

Johannes Berg johannes at sipsolutions.net
Wed Nov 28 00:06:20 EST 2007


On Tue, 2007-11-27 at 20:57 +1100, Paul Mackerras wrote:
> Johannes Berg writes:
> 
> > Contrary to what I claimed later in the thread, my 64-bit powerpc box
> > (quad-core G5) doesn't suffer from this problem.
> > 
> > Does anybody have any idea? I don't even know how to debug it further.
> 
> I see it on my G4 powerbook.  However, a compute-bound task runs just
> as fast (i.e. completes in the same elapsed time) as on older kernels,
> so it does look like it is just an accounting problem.  If the CPU was
> really spending more than half its time servicing hardware interrupts,
> the task should take more than twice as long to complete.

Exactly. So where do I look for the accounting bug?

johannes
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