[opensuse] CPU speed
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? -- Roger Oberholtzer -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
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: [snip] 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?
Yes I believe it is - I think it's AMDs dynamic frequency scaling "Cool'n'Quiet". Funny though, my own AMD Phenom 9500 seems to run four cores at 2.2GHz without change. -- Per Jessen, Zürich (21.6°C) http://www.hostsuisse.com/ - dedicated server rental in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On Wed 03 Jun 2015 10:25:59 AM CDT, 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?
Hi Run the command cpupower -c all frequency-info If set to ondemand they will switch as required, it will also provide info on boost states if applicable. If you want to set to max frequency all the time set it to performance. -- Cheers Malcolm °¿° LFCS, SUSE Knowledge Partner (Linux Counter #276890) SUSE Linux Enterprise Desktop 12 GNOME 3.10.1 Kernel 3.12.39-47-default up 5 days 14:26, 4 users, load average: 0.20, 0.20, 0.20 CPU AMD A4-5150M APU @ 3.3GHz | GPU Richland Radeon HD 8350G -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
I don't know that I want to have the CPU run faster than is needed. I would imagine that takes more power and generates more heat. Presumably, if the CPU is doing something, the clock speed is increased? Maybe I will try for a bit and see if things seem snappier. On Wed, Jun 3, 2015 at 3:32 PM, Malcolm <malcolmlewis@cableone.net> wrote:
On Wed 03 Jun 2015 10:25:59 AM CDT, 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?
Hi Run the command cpupower -c all frequency-info
If set to ondemand they will switch as required, it will also provide info on boost states if applicable.
If you want to set to max frequency all the time set it to performance.
-- Cheers Malcolm °¿° LFCS, SUSE Knowledge Partner (Linux Counter #276890) SUSE Linux Enterprise Desktop 12 GNOME 3.10.1 Kernel 3.12.39-47-default up 5 days 14:26, 4 users, load average: 0.20, 0.20, 0.20 CPU AMD A4-5150M APU @ 3.3GHz | GPU Richland Radeon HD 8350G
-- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
-- Roger Oberholtzer -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On 03/06/15 15:13, Roger Oberholtzer wrote:
I don't know that I want to have the CPU run faster than is needed. I would imagine that takes more power and generates more heat. Presumably, if the CPU is doing something, the clock speed is increased?
This is precisely so - when web browsing etc. I usually find 1 core running at full speed and seven 'just ticking over.' The one which runs fast changes periodically. When rendering my 3D graphics work, or calculating physics for it, all eight speed up immediately, and there is a clear relationship between cpu temp (and fan noise) and the number of cores running at top speed. The temperature falls off very quickly once the load reduces, and a slow temp fall-off is always indicative of the heatsink needing a clean.
Maybe I will try for a bit and see if things seem snappier.
I doubt you'll notice much, if any in day to day use. Dx -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
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
participants (5)
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Dylan -
John Andersen -
Malcolm -
Per Jessen -
Roger Oberholtzer