Re: BFS vs. mainline scheduler benchmarks and measurements
From: Nikos Chantziaras
Date: Tue Sep 08 2009 - 19:38:45 EST
On 09/09/2009 02:20 AM, Jiri Kosina wrote:
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).
Wouldn't that mean that a BFS-patched kernel would suffer from this too?
In any case, of the above, only fan control is active, and I've run with
it disabled on occasion (hot summer days, I wanted to just keep it max
with no fan control) with no change. As far as I can tell, the Asus P5E
doesn't have a TPM (the "Deluxe" and "VM" models seem to have one.) As
for memory errors, I use unbuffered non-ECC RAM which passes a
memtest86+ cycle cleanly (well, at least the last time I ran it through
one, a few months ago.)
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