Re: bogomips discrepancy on Intel Core2 Quad CPU

Justin Piszcz
2007-09-03T15:44:20Z

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@tmr.com>
> "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.