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Re: CPU frequency and custom kernel

On 11/21/2013 07:42 PM Sean Alexandre wrote:

I've built my own kernel, but the CPU runs faster (hotter, more fan noise, etc.)

I can't figure out why it's faster. Everything I've checked is the same between
the two kernels. If I boot to the Debian provided kernel the CPU runs at 800
MHz, but if I boot to my custom kernel it runs at 1.8 GHz. (These are baseline
speeds, after boot without running anything else.)

Here's what I've checked so far:

* Kernel versions are the same. The Debian version is 3.2.0-4-amd64 and the
   version I got from kernel.org is 3.2.52.
* The boot command line has the same paremeters for both:
   linux /vmlinuz-3.2.0-4-amd64 root=/dev/mapper/tuzo-root ro quiet
* Both boot to the same root file system, and use the same configuration files.
* The .config file used to build the custom kernel is the same as the one used
   to build the Debian kernel. (I'm going to pare it down to just what I need
   once I figure out this problem.)
* Both use the ondemand cpufreq governor.
I've found cpuspeed to be buggy... the speed at which the cpu runs seems to have little to do with the conditions specified in the config file. Recent kernel upgrades have improved cpuspeed somewhat (without any changes to the config file), but it's still nonsensical at times. 




Is there anything else I should check?

My next step would be to try and build the kernel source from the Debian
package instead of from kernel.org. Maybe this is a code difference?
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