On Thu, Feb 19, 2009 at 6:48 AM, Volker Armin Hemmann <[email protected]> wrote: > On Donnerstag 19 Februar 2009, Harry Holt wrote: >> On Thu, Feb 19, 2009 at 2:53 AM, Justin <[email protected]> wrote: >> > Martin Herrman schrieb: >> > > 2009/2/19 Thanasis <[email protected] >> > > <mailto:[email protected]>> >> > > >> > > # uname -a >> > > Linux wolfdale 2.6.28-gentoo-r2 #1 SMP PREEMPT Wed Feb 18 13:53:22 >> > >> > EET >> > >> > > 2009 x86_64 Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz GenuineIntel >> > > GNU/Linux >> > > >> > > Overclocked the core 2 duo (E8400) from 3 to 4GHz using motherboard >> > > BIOS settings. In mswindblows I can see the overclocked frequency >> > > (when cpu is under load), in linux /proc/cpuinfo never shows beyond >> > >> > the >> > >> > > stock 3GHz value. >> > > >> > > Q: Is /proc/cpuinfo showing the actual frequency? >> > > >> > > # cat cpuinfo >> > > processor : 0 >> > > vendor_id : GenuineIntel >> > > cpu family : 6 >> > > model : 23 >> > > model name : Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz >> > > stepping : 10 >> > > cpu MHz : 2997.000 >> > > cache size : 6144 KB >> > > physical id : 0 >> > > siblings : 2 >> > > core id : 0 >> > > cpu cores : 2 >> > > apicid : 0 >> > > initial apicid : 0 >> > > fpu : yes >> > > fpu_exception : yes >> > > cpuid level : 13 >> > > wp : yes >> > > flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr >> > > pge mca cmov >> > > pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall >> > > nx >> > >> > lm >> > >> > > constant_tsc arch_perfmon pebs bts rep_good pni dtes64 monitor >> > > ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm >> > > tpr_shadow vnmi flexpriority >> > > bogomips : 8099.96 >> > > clflush size : 64 >> > > cache_alignment : 64 >> > > address sizes : 36 bits physical, 48 bits virtual >> > > power management: >> > > >> > > processor : 1 >> > > vendor_id : GenuineIntel >> > > cpu family : 6 >> > > model : 23 >> > > model name : Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz >> > > stepping : 10 >> > > cpu MHz : 2997.000 >> > > cache size : 6144 KB >> > > physical id : 0 >> > > siblings : 2 >> > > core id : 1 >> > > cpu cores : 2 >> > > apicid : 1 >> > > initial apicid : 1 >> > > fpu : yes >> > > fpu_exception : yes >> > > cpuid level : 13 >> > > wp : yes >> > > flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr >> > > pge mca cmov >> > > pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall >> > > nx >> > >> > lm >> > >> > > constant_tsc arch_perfmon pebs bts rep_good pni dtes64 monitor >> > > ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm >> > > tpr_shadow vnmi flexpriority >> > > bogomips : 8099.74 >> > > clflush size : 64 >> > > cache_alignment : 64 >> > > address sizes : 36 bits physical, 48 bits virtual >> > > power management: >> > > >> > > >> > > I have noticed exactly the same while overclocking my Q9300 from it's >> > > stock 2.5 GHZ to 3.2 GHZ. Compilation / encode transactions do take >> > > much less time, so I assume that the BIOS information is correct and >> > > the /proc/ entry is false. >> > >> > If you downstep your cpu it is shown: >> > >> > model name : Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz >> > stepping : 11 >> > cpu MHz : 1600.000 >> > >> > But perhaps it just read the step and knows which frequency belongs to >> > that. >> >> I'm pretty sure /proc/cpuinfo is all static information, based on response >> from the chip, and not actual run-time frequencies. > > well - with an AMD k8 the correct frequencies are shown when overclocking. So > maybe its intel's fault.
I've seen different behaviours on different motherboards. I've got a Q6600, stock 266 x 9 that I run it at 400 x 8. My last Asus got the bus freq right but assumed the multiplier was always 9 and ondemand clock scaling didn't work. On my current DFI the proc entry is correct and ondemand does work. I can't imagine a lot of kernel develoeprs overclock their computers so its not surprising no one has noticed this. Wil
