Re: k10h post-BIOS patch effects

Guys,

>Which Linux distro do you use ? You should kill all the
>"power-sensual" daemons (like powersaved in SuSE) and remove the
>corresponding kernel daemons like cpufreq.

I tried two linux distros: kubuntu hardy heron & Fedora Core 9.  FC9 does
it a *lot* less than kubuntu, but it still does it.  I have turned off
"cool & quiet" in the bios, and cpuinfo shows full speed even as my
timings drop by half.  I verified that cpufreq doesn't work after the BIOS
turnoff (the scaling directiries are missing from ACPI).

I more & more suspect the problem is in the motherboard.  Dean (I think it was)
mentioned that thermal throttling is broken in the Phenom; I wonder if
the mobo assumes it works and does some voltage things it can't handle
in response to OS calls.

Whatever it is, it is affected by OS, so it is not pure hardware.  But,
I wonder if the OS sends some signal that the mobo should ignore,
but instead attempts something the k10h can't do . . .

Anyway, if anyone can tell me OS & mobo combinations that they have seen
work for the Phenom, I'd appreciate it.

>BIOS patch was declared as leading to some performance degradation.

Yeah, but I did not expect that massive die-off for a cache-dominated
algorithm like GEMM.  For HPC, the slowdown is massive and pervasive,
but the TLB bug is triggered daily.

>The better choice is to patch Linux kernel (the patch was published on
>AMD x86-64 electronic conference) - it must give minor performance
>decrease.

Last time I checked, this was not in the standard linux kernel, or even
a supporte patch, but just some example code on some mailing list, where
the AMD guy says, "I wouldn't use this if I were you" . . .

Cheers,
Clint

**************************************************************************
** R. Clint Whaley, PhD ** Assist Prof, UTSA ** www.cs.utsa.edu/~whaley **
**************************************************************************

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