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Old 06-08-2009, 02:47 AM   #1
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Unhappy cpu frequency is divided between two core of core2duo or dualcore or intel atom HT

Hello , This is my first question on forum....

I had Intel Atom with HT...
My linux kernel is enabled with SMP
when I do "cat /proc/cpuinfo" I can see two processor and frequency on each processor is 2400.000 (my cpu freq is 3Ghz) .

If I disabled SMP in linux kernel whether all my 3Ghz will be used by one core or it will be divided between two cores...also if i disabled from bios what are result and how to verify it ??
Also How to check the running frequency which kernel is using ....

Old 06-08-2009, 06:28 AM   #2
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The current speed of the processor will be shown in /proc/cpuinfo. Most modern Linux distributions come with power management and CPU frequency scaling enabled by default, so what you're seeing is that at the moment your CPU is running at 2.4GHz rather than its full 3GHz speed. This is as expected and probably what you want - minimize power consumption and heat while delivering full performance whenever needed.

Disabling or enabling SMP in the kernel will not directly affect CPU frequency scaling. If you have a dual core CPU with hyperthreading enabled you should see four cores (two actual cores with two threads available on each), so I suppose you have a single core with hyperthreading.

You will not see any performance gain by disabling SMP, rather the opposite since most Linux application (and indeed the OS itself) is thread-aware.
Old 06-08-2009, 06:34 AM   #3
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If you want to see the speed as reported by cat /proc/cpuinfo increase to your CPU's rated speed, try the following. Open two terminals; in one, paste the following:
cat /dev/urandom > /dev/null
Then, in the other, check the output of cat /proc/cpuinfo again. The reported CPU speeds should have increased to the processor maximum. Kill the cat /dev/urandom process in the first terminal after you're done checking the speeds (all this command does is make the CPU usage go to 100% and output the results to the bit-bin (/dev/null)).

Last edited by pwc101; 06-08-2009 at 06:37 AM.
Old 06-09-2009, 02:45 AM   #4
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Thanks a lot..


frequency, smp

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