On Tue, Apr 29, 2014 at 10:22:29PM +0200, Thomas Bohl wrote: > Hello List, > > I installed 5.5-current, both with i386 and amd64, on a ASRock > AD2550-ITX mainboard [1] which has a Intel Dual-Core Atom D2550 CPU on > board. > On the i386 version sysctl shows the MIB name hw.setperf and therefore > it's possible to throttle the CPU down. The amd64 version on the other > hand doesn't show hw.setpref and it's not possible to manipulate the > CPU speed through that value. > > I have played around with the BIOS settings and haven't found something > that makes a difference. > > It looks as if this problem isn't new. [2] Apart from sticking to i386 > of course, is there anything I could try to manipulate the CPU speed? > > cpu0 at mainbus0: apid 0 (boot processor) > cpu0: Intel(R) Atom(TM) CPU D2550 @ 1.86GHz, 1867.07 MHz > cpu0: > FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,DTES64,MWAIT,DS-CPL,TM2,SSSE3,CX16,xTPR,PDCM,MOVBE,NXE,LONG,LAHF,PERF,ITSC
We only do speedstep if the processor advertises that speedstep is supported in cpuid (ie there should be a 'EST' flag above). According to http://ark.intel.com/products/65470/Intel-Atom-Processor-D2550-(1M-Cache-1_86-GHz) it doesn't do speedstep as well. i386 fakes a table with high/low values for older processors that still have a fsb, which was mostly used before the code to fetch tables from acpi was added.
