Re: SpeedStep in DomUs?

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

On 12.07.2010 12:25, Stefan Groà wrote:
> Thanks a lot, now i got realcpu0 pinned to vcpu0 and dom0 has only this
> cpu, i think that matches the restriction for using cpufreq=dom0-kernel.
> But sysctl still doesn't give me any est-options. So i looked at the
> kernel-config and found out that "option ENHANCED_SPEEDSTEP" is missing
> in the amd64 XEN3_DOM0. Trying to compile with the optionline simply
> added to a copy of XEN3_DOM0 config named LENA gives the following error:
> 
> #      link  LENA/netbsd
> ld -Map netbsd.map --cref -T
> ../../../../arch/amd64/conf/kern.ldscript.Xen -Ttext 0xffffffff80100000
> -e start -X -o netbsd ${SYSTEM_OBJ} ${EXTRA_OBJ} vers.o
> identcpu.o: In function `cpu_identify':
> ../../../../arch/x86/x86/identcpu.c:713: undefined reference to `est_init'
> *** Error code 1
> 
> Stop.
> make: stopped in /usr/src/sys/arch/amd64/compile/LENA
> 
> The relevant lines in identcpu.c seem to be these:
> 
> #ifdef ENHANCED_SPEEDSTEP
>       if (cpu_feature2 & CPUID2_EST) {
>               if (rdmsr(MSR_MISC_ENABLE) & (1 << 16))
>                       est_init(cpu_vendor);
>       }
> #endif /* ENHANCED_SPEEDSTEP */
> 
> Am i right, that "est_init(cpu_vendor)" is a function call, and the
> linker stops for not knowing the function? Can i do something about it
> (well, i'm a newbie in these things)? Maybe est isn't enabled by default
> just for cautiousness -- or is it for harder reasons?

Ahhh yes, I remember now; It is not as trivial as it seems, I did not
pull it up to NetBSD-5, due to ACPI support concerns with the kernel; I
fear you would have to try that with a -current kernel:

http://mail-index.netbsd.org/source-changes/2009/08/05/msg223683.html

Link to a current kernel:

ftp://nyftp.netbsd.org/pub/NetBSD-daily/HEAD/201007110000Z/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz

If it works with current, I could give you a patch to enable est under
-5 too. Note that Xen 3.3 is required.

-- 
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost