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SubjectRe: [RFC][PATCH] iowait statistics
Date
On 14 May 2002 00:18, Andrew Morton wrote:
> Rik van Riel wrote:
> > 4) on SMP systems the iowait time can be overestimated, no big
> > deal IMHO but cheap suggestions for improvement are welcome
>
> I suspect that a number of these statistical accounting mechanisms
> are going to break. The new irq-affinity code works awfully well.
>
> The kernel profiler in 2.5 doesn't work very well at present.
> When investigating this, I ran a busy-wait process. It attached
> itself to CPU #3 and that CPU received precisely zero interrupts
> across a five minute period. So the profiler cunningly avoids profiling
> busy CPUs, which is rather counter-productive. Fortunate that oprofile
> uses NMI.

What, even local APIC interrupts did not happen on CPU#3
in these five mins?
--
vda
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