On Mon 10 Sep 2007 00:09, Erik Trulsson wrote: > On Mon, Sep 10, 2007 at 12:04:45AM +0200, Martin Tournoij wrote: > > On Sun 09 Sep 2007 22:09, Erik Trulsson wrote: > > > On Sun, Sep 09, 2007 at 10:50:25PM +0200, Martin Tournoij wrote: > > > > I'm trying to get the CPU frequency in C: > > > > > > > > #include <unistd.h> > > > > #include <time.h> > > > > #include <ctype.h> > > > > #include <sys/sysctl.h> > > > > #include <stdio.h> > > > > #include <sys/time.h> > > > > > > > > int main() > > > > { > > > > int mib[2]; > > > > size_t size; > > > > struct clockinfo clockrate; > > > > > > > > mib[0] = CTL_KERN; > > > > mib[1] = KERN_CLOCKRATE; > > > > size = sizeof clockrate; > > > > sysctl(mib, 2, &clockrate, &size, NULL, 0); > > > > > > > > fprintf(stdout, "hz: %i\n", clockrate.hz); > > > > fprintf(stdout, "tick: %i\n", clockrate.tick); > > > > fprintf(stdout, "spare: %i\n", clockrate.spare); > > > > fprintf(stdout, "stathz: %i\n", clockrate.stathz); > > > > fprintf(stdout, "profhz: %i\n", clockrate.profhz); > > > > > > > > return 0; > > > > } > > > > > > > > I tried to run this on two machines (one machine with hw.clockrate: > > > > 1378 and > > > > the other 797) and it outputs the same on both: > > > > hz: 1000 > > > > tick: 1000 > > > > spare: 0 > > > > stathz: 133 > > > > profhz: 666 > > > > > > > > The profhz value suggest the devil is at work :D although it's probably > > > > a some > > > > stupid mistake on my part :/ Can anyone help? > > > > > > None of the kern.clockrate entries has any particular relationship with > > > the > > > CPU clock frequency, so it is not unexpected that you would get the same > > > output from both machines. > > > > > > I think looking at hw.clockrate is the most portable you can get. > > > If your CPU is using Cool'n'Quiet or the Intel equivalent you can also > > > look at dev.cpu.N.freq for the current frequency. > > > > I got confused because they both have the same name ... do'h > > > > hw.clockrate doesn't seem to available through C(?), > > Of course it is. Using sysctlbyname(3) to access it works fine: > > #include <unistd.h> > #include <sys/sysctl.h> > #include <stdio.h> > > int main() > { > size_t size; > int clockrate; > > size = sizeof clockrate; > sysctlbyname("hw.clockrate", &clockrate, &size, NULL, 0); > > fprintf(stdout, "hz: %i\n", clockrate); > return 0; > } > > > hw.clockrate does however only seem to exist on i386 and amd64 architectures > so if you are running on something else you will have to find some > alternative solution. (Parsing the dmesg(8) output?) > > > > > exec-ing sysctl > > hw.clockrate would work, but that's not very elegant... > > > > dev.cpu.0.freq doesn't seem to exists on my (Athlon) CPU, it > > does on my PIII CPU though. > > It partly depends on the CPU, and mostly on the BIOS if the cpufreq(4) > kernel module will be activated (assuming it has been loaded in the first > place of course.)
Thought you could only fetch the sysctl values defined in sys/sysctl.h with sysctl()/sysctlbyname(), apparently not... Thank you for the help Erik and Mel! _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"