Re: bogomips discrepancy on Intel Core2 Quad CPU

From: Justin Piszcz
Date: Mon Sep 03 2007 - 11:44:50 EST




On Mon, 3 Sep 2007, Bill Davidsen wrote:

Bauke Jan Douma wrote:
$> uname -a
Linux skyscraper 2.6.22.5 #7 SMP PREEMPT Sun Sep 2 12:12:25 CEST 2007 i686 GNU/Linux

$> cat /proc/cpuinfo | grep bogomips
bogomips : 4813.46
bogomips : 4810.91
bogomips : 4810.91
bogomips : 10583.94

The latter seems way off base.
Prod me for more info.

I see this occasionally on a dual, speedstep (or similar) finds a way to throttle down the cores under light load. I suspect that if you load the system:

for n in 1 2 3 4; do
nice -19 bash -c 'while true; do a=$RANDOM; done' &
done

Then you should see your bogomips rise on all cores.


bjd

[... copy of output snipped, see the O.P. ...]

--
Bill Davidsen <davidsen@xxxxxxx>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
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$ uname -a
Linux p34.internal.lan 2.6.22 #2 SMP Mon Jul 16 18:40:31 EDT 2007 x86_64 GNU/Linux

$ cat /proc/cpuinfo | grep bogomips
bogomips : 4797.72
bogomips : 4795.16
bogomips : 4795.21
bogomips : 4795.19

Mine is fine, not using any speedstep here.

Justin.
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