On Tue, 16 Nov 2010, Andreas Herrmann wrote: > On Mon, Nov 15, 2010 at 11:01:05AM -0500, Len Brown wrote: > > From: Len Brown <len.brown@xxxxxxxxx> > > > > turbostat displays actual processor frequency on modern > > Intel processors. Note that this capability depends on free-running > > APERF and MPERF MSRs, which were cleared by the acpi_cpufreq > > driver up through Linux-2.6.29. > > Why isn't cpufreq-aperf sufficient for showing the actual frequency? > The tool can handle both AMD and Intel CPUs. Looking over its source code, I don't see any reason that cpufreq-aperf wouldn't be sufficient for showing actual frequency, were that your goal. I hadn't heard of this tool until your note. I complied it, but I guess I'm too lazy to figure out why it didnt' run. It seems somewhat elaborate as compared to the task at hand... > There is a CPUID flag which can be checked for APERF/MPERF existence, > no need to enforce a general vendor check like this: > > $ ./turbostat > CPUID: AuthenticAMD != GenuineIntel turbostat isn't very interesting on systems that don't have a reliable TSC or C-state residency MSRs. AFAIK, AMD has neither. If you have information to the contrary and can test it on AMD hardware, I'd be happy to enable AMD, as I have neither. > > On Intel Core i3/i5/i7 (Nehalem) and newer processors, > > turbostat displays residency in idle power saving states. > > Can't this be added to cpuidle-info (see branch cpupowerutils in > git://git.kernel.org/pub/scm/utils/kernel/cpufreq/cpufrequtils.git)? I suppose it could if somebody were in need of a hobby. However, if you want a big tool in this space, you'd probably be better off running powertop2, which will incorporate what turbostat does, and more. > BTW, gcc v4.4 throws several warnings when compiling your > code: thanks, I'll fix these. cheers, Len Brown, Intel Open Source Technology Center _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
