Re: [gentoo-user] Check CPU for throttling
On 05/10/2011 02:36:33 AM, Volker Armin Hemmann wrote: On Sunday 08 May 2011 12:59:57 Helmut Jarausch wrote: On 05/08/2011 11:21:06 AM, Florian Philipp wrote: sys-process/atop shows current CPU freqency I use it to check the effect of sys-power/powernowd why are you using powernowd? Why not? It's a daemon which reduces the CPU speed under certain circumstances. This not only saves power but it reduce the noise produced by the fan. Helmut.
Re: [gentoo-user] Check CPU for throttling
On Tuesday 10 May 2011 08:27:42 Helmut Jarausch wrote: On 05/10/2011 02:36:33 AM, Volker Armin Hemmann wrote: On Sunday 08 May 2011 12:59:57 Helmut Jarausch wrote: On 05/08/2011 11:21:06 AM, Florian Philipp wrote: sys-process/atop shows current CPU freqency I use it to check the effect of sys-power/powernowd why are you using powernowd? Why not? It's a daemon which reduces the CPU speed under certain circumstances. just like the kernel. Only the kernel does it better. This not only saves power but it reduce the noise produced by the fan. fanspeed - if you have a pwm fan. Seriously, powernowd is so not needed. Just built a kernel with ondemand cpu governor. You are done.
Re: [gentoo-user] Check CPU for throttling
On 05/10/2011 02:44:26 PM, Volker Armin Hemmann wrote: On Tuesday 10 May 2011 08:27:42 Helmut Jarausch wrote: On 05/10/2011 02:36:33 AM, Volker Armin Hemmann wrote: On Sunday 08 May 2011 12:59:57 Helmut Jarausch wrote: On 05/08/2011 11:21:06 AM, Florian Philipp wrote: sys-process/atop shows current CPU freqency I use it to check the effect of sys-power/powernowd why are you using powernowd? Why not? It's a daemon which reduces the CPU speed under certain circumstances. just like the kernel. Only the kernel does it better. This not only saves power but it reduce the noise produced by the fan. fanspeed - if you have a pwm fan. Seriously, powernowd is so not needed. Just built a kernel with ondemand cpu governor. You are done. Hi, I've just tried that, but it doesn't work (at least, as the output of atop is concerned) dmesg shows cpuidle: using governor ladder cpuidle: using governor menu Am I missing something? Thanks for a hint, Helmut.
Re: [gentoo-user] Check CPU for throttling
Am 10.05.2011 16:34, schrieb Helmut Jarausch: Am I missing something? Look at 'grep MHz /proc/cpuinfo' to see if your CPU is throttling correctly. signature.asc Description: OpenPGP digital signature
Re: [gentoo-user] Check CPU for throttling
On 05/10/2011 04:42:52 PM, Sebastian Beßler wrote: Am 10.05.2011 16:34, schrieb Helmut Jarausch: Am I missing something? Look at 'grep MHz /proc/cpuinfo' to see if your CPU is throttling correctly. And that tells me that the CPU is running at full speed (3 GHz in my case) although all CPUs are idle. Helmut.
Re: [gentoo-user] Check CPU for throttling
Am 10.05.2011 16:49, schrieb Helmut Jarausch: And that tells me that the CPU is running at full speed (3 GHz in my case) although all CPUs are idle. What does cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor and cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies and cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors say? Greetings Sebastian signature.asc Description: OpenPGP digital signature
Re: [gentoo-user] Check CPU for throttling
On 05/10/2011 04:57:05 PM, Sebastian Beßler wrote: Am 10.05.2011 16:49, schrieb Helmut Jarausch: And that tells me that the CPU is running at full speed (3 GHz in my case) although all CPUs are idle. What does cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor userspace and cat /sys/devices/system/cpu/cpu0/cpufreq/ scaling_available_frequencies 300 230 180 80 and cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors say? userspace ondemand performance Do I have to disable the userspace governor? Thanks, Helmut.
Re: [gentoo-user] Check CPU for throttling
Am 10.05.2011 17:03, schrieb Helmut Jarausch: Do I have to disable the userspace governor? Yes you have to. The userspace governor needs a external programm to set the cpu speed. Set it to ondemand should do the trick because ondemand lets the kernel choose the right cpu speed. Greetings Sebastian signature.asc Description: OpenPGP digital signature
Re: [gentoo-user] Check CPU for throttling
On 05/10/2011 04:57:05 PM, Sebastian Beßler wrote: Am 10.05.2011 16:49, schrieb Helmut Jarausch: And that tells me that the CPU is running at full speed (3 GHz in my case) although all CPUs are idle. What does cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor and cat /sys/devices/system/cpu/cpu0/cpufreq/ scaling_available_frequencies and cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors say? I have tried echo ondemand /sys/devices/system/cpu/cpu0/cpufreq/ scaling_governor and now I see an effect but not as good as powernowd e.g. I have stopped processed temporarily so that the CPU usage fell down to 1% (max). Still after waiting some minutes, only one core scaled down to 800 MHz and a a second one to 2.3 GHz. At least, powernowd it much more agressive. If some cores are idle for a few seconds it scales these down stepwise to the lowest frequency. Helmut.
Re: [gentoo-user] Check CPU for throttling
On Tuesday 10 May 2011 16:34:53 Helmut Jarausch wrote: On 05/10/2011 02:44:26 PM, Volker Armin Hemmann wrote: On Tuesday 10 May 2011 08:27:42 Helmut Jarausch wrote: On 05/10/2011 02:36:33 AM, Volker Armin Hemmann wrote: On Sunday 08 May 2011 12:59:57 Helmut Jarausch wrote: On 05/08/2011 11:21:06 AM, Florian Philipp wrote: sys-process/atop shows current CPU freqency I use it to check the effect of sys-power/powernowd why are you using powernowd? Why not? It's a daemon which reduces the CPU speed under certain circumstances. just like the kernel. Only the kernel does it better. This not only saves power but it reduce the noise produced by the fan. fanspeed - if you have a pwm fan. Seriously, powernowd is so not needed. Just built a kernel with ondemand cpu governor. You are done. Hi, I've just tried that, but it doesn't work (at least, as the output of atop is concerned) dmesg shows cpuidle: using governor ladder cpuidle: using governor menu that is a different can of worms Am I missing something? yes: *- 'ondemand' cpufreq policy governor
Re: [gentoo-user] Check CPU for throttling
Apparently, though unproven, at 17:14 on Tuesday 10 May 2011, Helmut Jarausch did opine thusly: On 05/10/2011 04:57:05 PM, Sebastian Beßler wrote: Am 10.05.2011 16:49, schrieb Helmut Jarausch: And that tells me that the CPU is running at full speed (3 GHz in my case) although all CPUs are idle. What does cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor and cat /sys/devices/system/cpu/cpu0/cpufreq/ scaling_available_frequencies and cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors say? I have tried echo ondemand /sys/devices/system/cpu/cpu0/cpufreq/ scaling_governor and now I see an effect but not as good as powernowd e.g. I have stopped processed temporarily so that the CPU usage fell down to 1% (max). Still after waiting some minutes, only one core scaled down to 800 MHz and a a second one to 2.3 GHz. At least, powernowd it much more agressive. If some cores are idle for a few seconds it scales these down stepwise to the lowest frequency. The authors of powertop (employed by Intel) researched this topic extensively and wrote up their findings on the project website and in the package docs. In summary, it goes something like this: Userspace cpu freq daemons are a waste of time, it takes excessive energy to step wise change performance up and down. What you really want is for the cpu to run full speed when it has something to do, get it done as quickly as possible then rapidly fall back to the lowest idle speed once the job is complete. That is how the ondemand governor is written. I suppose this step-down-through-the-levels nonsense comes from flawed comparisons with combustion engines and turbines - it makes sense to ramp these up and down. It does not make sense to do this with a cpu as a cpu is a completely different beast altogether. It is either doing something or nothing; actually it never does nothing - it always does something even if that is just the no-op instruction in a loop. And cpus do not accelerate like engines and use almost no additional power to go from min to max speed. So when something useful comes along to do, just switch over to max speed and get the job done. Really, this powernowd stuff looks neat on paper but the actual numbers say otherwise. Just enable ondemand, disable everything else, and et the kernel get on with doing what it does best: the kernel should never try and be clever and second guess you, that way lies madness. Similarly, you should never try and be clever and second guess the kernel. That way also lies madness. -- alan dot mckinnon at gmail dot com
Re: [gentoo-user] Check CPU for throttling
On 05/10/2011 08:36 AM, Alan McKinnon wrote: I suppose this step-down-through-the-levels nonsense comes from flawed comparisons with combustion engines and turbines - it makes sense to ramp these up and down. It does not make sense to do this with a cpu as a cpu is a completely different beast altogether. It is either doing something or nothing; actually it never does nothing - it always does something even if that is just the no-op instruction in a loop. And cpus do not accelerate like engines and use almost no additional power to go from min to max speed. So when something useful comes along to do, just switch over to max speed and get the job done. That's not exactly true. It does take time, aka latency, to move CPUs out of sleep states. Sleep states are partially related to this because once the load on a CPU goes to zero, the governor will, depending on your configuration, put the CPU into a sleep state to conserve power. Waking that sleeping CPU from its deepest sleep state takes an enormous amount of time, in terms of CPU time, so it sometimes behooves the scheduler to be a bit less dogmatic about putting CPUs to bed while there's still work to do.
Re: [gentoo-user] Check CPU for throttling
On Sunday 08 May 2011 12:59:57 Helmut Jarausch wrote: On 05/08/2011 11:21:06 AM, Florian Philipp wrote: sys-process/atop shows current CPU freqency I use it to check the effect of sys-power/powernowd why are you using powernowd?
[gentoo-user] Check CPU for throttling
Hi list! Does someone know a tool that measures CPU performance and gives live-updates on it? My problem is as follows: I have a desktop PC where the case is too small to include the custom CPU cooler with fan. However, because the power supply sits directly above the CPU and the CPU cooler is reasonably effective, I've simply removed the fan from the CPU cooler and let the fan from the power supply act as the CPU fan. This works surprisingly well and usually, the CPU runs at 50°C. During tests with app-benchmarks/cpuburn, the CPU got as hot as 74°C. According to lm_sensors, this is the threshold for critical temperature (though I find it a bit low - I've seen CPUs running as high as 90°C). Therefore I suspect that the CPU gets throttled but I cannot verify this with cpuburn because this tool does not output performance figures. Because of that I'm in a need for a similar tool that also outputs FIPS, iterations per second or some other figure while running so that I can monitor it for any performance drops. I guess I could just use mencoder and watch framerates or I could code something myself but maybe someone knows a better tool for this. Thanks in advance! Florian Philipp signature.asc Description: OpenPGP digital signature
Re: [gentoo-user] Check CPU for throttling
On 05/08/2011 11:21:06 AM, Florian Philipp wrote: sys-process/atop shows current CPU freqency I use it to check the effect of sys-power/powernowd Helmut. Hi list! Does someone know a tool that measures CPU performance and gives live-updates on it? My problem is as follows: I have a desktop PC where the case is too small to include the custom CPU cooler with fan. However, because the power supply sits directly above the CPU and the CPU cooler is reasonably effective, I've simply removed the fan from the CPU cooler and let the fan from the power supply act as the CPU fan. This works surprisingly well and usually, the CPU runs at 50°C. During tests with app-benchmarks/cpuburn, the CPU got as hot as 74°C. According to lm_sensors, this is the threshold for critical temperature (though I find it a bit low - I've seen CPUs running as high as 90°C). Therefore I suspect that the CPU gets throttled but I cannot verify this with cpuburn because this tool does not output performance figures. Because of that I'm in a need for a similar tool that also outputs FIPS, iterations per second or some other figure while running so that I can monitor it for any performance drops. I guess I could just use mencoder and watch framerates or I could code something myself but maybe someone knows a better tool for this. Thanks in advance! Florian Philipp -- Helmut Jarausch Lehrstuhl fuer Numerische Mathematik RWTH - Aachen University D 52056 Aachen, Germany
Re: [gentoo-user] Check CPU for throttling
Have you considered installing a low profile fan like Delta EFB0612MA 60x60x10[mm] ?
Re: [gentoo-user] Check CPU for throttling
Am 08.05.2011 13:01, schrieb Thanasis: Have you considered installing a low profile fan like Delta EFB0612MA 60x60x10[mm] ? I did. But I still had the current cooler available. I don't want to spend money on a new cooler if it is not necessary. Since I know even Pentium 4 cooled in that way, it was worth a try. signature.asc Description: OpenPGP digital signature
