Messages in this thread | | | Date | Sun, 09 Sep 2007 01:03:57 +0200 | From | Bauke Jan Douma <> | Subject | Re: bogomips discrepancy on Intel Core2 Quad CPU |
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Bill Davidsen wrote on 03-09-07 16:47: > 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.
Sorry for now getting back on this sooner. Other matters forced it to the backburner.
I don't have Speedstep enabled on this machine's kernel (as a matter of fact, the entire cpufreq Kconfig subtree is unchecked). Needless to say running your bash script doesn't change the values in any way.
I'd say the 4800-something bogomips value is the correct one (for a 2.4GHz CPU -- at least that's what I recall on single-CPU machines, mostly bogomips being approx. twice the rated CPU speed), and the 10000-something is the one off base.
Btw., the 10000 can be something like 12000-odd after a machine reboot, and readout on a different CPU. The rest are all ca. 4810. Odd indeed.
bjd
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