Re: BFS vs. mainline scheduler benchmarks and measurements

[Jiri Kosina]

On Wed, 9 Sep 2009, Nikos Chantziaras wrote:

> > > Here the result:
> > > 
> > >       http://foss.math.aegean.gr/~realnc/pics/latop2.png
> > > 
> > > Again: this is on an Intel Core 2 Duo CPU.
> > 
> > Just an idea: Maybe some system management code hits you?
> 
> I'm not sure what is meant with "system management code."

System management interrupt happens when firmware/BIOS/HW-debugger is 
executed in privilege mode so high, that even OS can't do anything about 
that.

It is used in many situations, such as

- memory errors
- ACPI (mostly fan control)
- TPM

OS has small to none possibility to influence SMI/SMM. But if this would 
be the cause, you should probably obtain completely different results on 
different hardware configuration (as it is likely to have completely 
different SMM behavior).

-- 
Jiri Kosina
SUSE Labs, Novell Inc.
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