Messages in this thread | | | From | Larry Finger <> | Subject | Regression in 4.8 - CPU speed set very low | Date | Fri, 9 Sep 2016 12:39:27 -0500 |
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I have found a regression in kernel 4.8-rc2 that causes the speed of my laptop with an Intel(R) Core(TM) i7-4600M CPU @ 2.90GHz to suddenly have a maximum cpu frequency of ~400 MHz. Unfortunately, I do not know how to trigger this problem, thus a bisection is not possible. It usually happens under heavy load, such as a kernel build or the RPM build of VirtualBox, but it does not always fail with these loads. In my most recent failure, 'hwinfo --cpu' reports cpu MHz of 396.130 for #3. The bogomips value is 5787.73, and the cpu clock before the fault is 3437 MHz. Nothing is logged when this happens.
If I were to get a patch that would show a backtrace when the maximum CPU frequency is changed, perhaps it would be possible to track this bug.
Sorry that I can not be more specific.
Larry
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