Re: frequency scaling on D525MW not working properly

[Sven Gaerner <sgaerner@xxxxxxx>]

On Wed, Jul 25, 2012 at 10:02:58AM +0200, Sascha Wildner wrote:
> As Brian Mastenbrook pointed out in a comment on the digest, the
> Atom should support P4TCC:
> 
> http://www.shiningsilence.com/dbsdlog/2012/07/24/10128.html
> 
> Check your CPU features in dmesg. It should show the TM feature, as
> it does on my Atom 330 (second to last):
> 
> Features=0xbfe9fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
> 
> Compiling the kernel with CPU_ENABLE_TCC gives new dmesg and sysctls:
> 
> almsta# grep TCC /var/run/dmesg.boot
> Pentium 4 TCC support enabled, current performance 13%
> almsta# sysctl hw.p4tcc
> hw.p4tcc.cpuperf: 13
> hw.p4tcc.cpuperf_performance: 100
> hw.p4tcc.cpuperf_economy: 13
> 
> However, a quick test with factor(6) showed no difference between 13
> and 100:
> 
> almsta# sysctl hw.p4tcc.cpuperf=100
> hw.p4tcc.cpuperf: 13 -> 100
> almsta# time factor 234241111111
> 234241111111: 7 7 4780430839
> 4.726u 0.000s 0:04.77 98.9%     16+66k 0+0io 0pf+0w
> 
> almsta# sysctl hw.p4tcc.cpuperf=13
> hw.p4tcc.cpuperf: 100 -> 13
> almsta# time factor 234241111111
> 234241111111: 7 7 4780430839
> 4.726u 0.007s 0:04.77 98.9%     16+66k 0+0io 0pf+0w
> 
> Anyway, if your system is i386, try out adding "options
> CPU_ENABLE_TCC" to the config and see what it gives.
> 
> I'll see later today about providing it for x86_64 too.
> 
> Sascha

Thanks a lot for all the hints. I will try this options these days and get
back with the results.

Sven