On 06/03/2015 01:25 AM, Roger Oberholtzer wrote:
I have a system (not a laptop) that has an "AMD Phenom(tm) II X6 1100T Processor", as reported in /proc/cpuinfo. I have been monitoring the CPU speed as reported there and I see that quite often the speed is reported as 800 MHz instead of 3300 MHz. For example, I ran the four commands pretty much one after the other. The speed is changing all the time:
roger@acme:~> cat /proc/cpuinfo | grep "cpu MHz" cpu MHz : 3300.000 cpu MHz : 3300.000 cpu MHz : 800.000 cpu MHz : 3300.000 cpu MHz : 3300.000 cpu MHz : 3300.000 roger@acme:~> cat /proc/cpuinfo | grep "cpu MHz" cpu MHz : 800.000 cpu MHz : 3300.000 cpu MHz : 3300.000 cpu MHz : 800.000 cpu MHz : 3300.000 cpu MHz : 3300.000 roger@acme:~> cat /proc/cpuinfo | grep "cpu MHz" cpu MHz : 800.000 cpu MHz : 800.000 cpu MHz : 800.000 cpu MHz : 800.000 cpu MHz : 3300.000 cpu MHz : 3300.000 roger@acme:~> cat /proc/cpuinfo | grep "cpu MHz" cpu MHz : 800.000 cpu MHz : 2500.000 cpu MHz : 3300.000 cpu MHz : 800.000 cpu MHz : 3300.000 cpu MHz : 3300.000
The system is busy when this is run. So I cannot think there are unused CPUs that are made to slow down because they have nothing to do. Especially changing as often as they seem to be changing.
Is this expected behavior?
Totally normal. As for the system being "busy", you have to realize that tasks don't necessarily jump from CPU to CPU on a whim, and constantly bouncing tasks to different CPUs that are perceived as running slowly does not improve performance nor power saving. Tasks can't always make use of multiple cores. A great deal of code is single threaded over large sections, which means another idle core can't necessarily be pressed into service. Besides, your instantaneous reading is not indicative of anything in particular. My recommendation is to STOP watching this. It will drive you to micromanaging the cpu speed, which, with all due respect, you are poorly equipped to do. The kernel's scheduler is way better at this than you will ever be. The only conclusion you can draw is your machine is far less busy than you think. If you have some specific problem you are trying to solve, let us know that it is. If the machine is running slowly in your opinion, look into the power profile and set it to high performance. Other than that, the breakfast sausage tastes much better if you don't watch how it is made. -- After all is said and done, more is said than done. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org