On 08/07/2012 01:09 PM, Mathieu Roy wrote:
Hello, Is there any way to get the actual real hardware CPU frequency in the case of an overclocked CPU? Running at max, I get # cpufreq-info --hwfreq 3000000 # cpufreq-info --freq 3000000
Both command lines eventually query the frequency from an ACPI table. This table will be filled at boot time by the BIOS. Now it depends on how you overclock your system. If you use the BIOS, it _could_ adapt the ACPI table and enter the actual values here, but obviously it does not do this. If you do this outside of the BIOS, ACPI is usually not altered, so you are out of luck then.
However, dmidecode shows, according to BIOS settings: Version: AMD Athlon(tm) II X4 640 Processor External Clock: 230 MHz Max Speed: 3700 MHz Current Speed: 3450 MHz
So this gives a hint that the BIOS knows about the overclocked system. I guess that it just does not report this into the _PSS object, probably because the official recommendation in the AMD manuals is to use 200 MHz as the base frequency.
Which frequency value is the correct one? I assume cpufreq does not override the BIOS overclocking settings (external clock at 230 instead of 200, hence the CPU at 3450 instead of 3000), so is there any way for cpufreq to adjust and report correct values?
cpufreq just reports the _PSS ACPI content and does not alter or override any settings. I guess it is out of scope for the rather generic cpufreq subsystem to query any actual overclocked system bus frequencies and report those values instead.
However you could use more hardware dedicated tools to read the data directly from the system and compute the actual frequencies. As I am not an overclocker, I don't know of any Linux tools who do this, but maybe someone from the list does.
Regards, Andre. -- Andre Przywara AMD-Operating System Research Center (OSRC), Dresden, Germany -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
