frequency scaling on D525MW not working properly

[Sascha Wildner]

On Sun, 22 Jul 2012 13:46:41 +0200, Sven Gaerner <sgaerner at gmx.net> wrote:

> Hello, I bought an Atom based Intel D525MW board. DragonFly release is  
> running
> on that system. But I have a few minor issues. The CPU is getting  
> somewhat warm
> (about 55 degrees celsius).
> [...]

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