Re: Via 694X based SMB boards (Apollo Pro133A)

[Nate Lawson <nate-Y6VGUYTwhu0@public.gmane.org>]

On Thu, 15 Jan 2004, Dino Klein wrote:
> > If you're looking to do throttling, some SMP boards support it.  The most
> > common way is with a shared P_BLK.  Either both Processor objects in the
> > ASL will have the same P_BLK or one will have it and the other will have a
> > NULL entry.  Either way, setting throttling through the P_BLK _ONCE_ (not
> > once per processor) sets the throttling level.
>
> Actually, I did play with the throttling, but not through the ACPI
> driver. I wrote directly to the register, and the system was reduced to
> ~5% (according to the datasheets) of it's former glory. I did that with
> both CPUs on the board, which makes me wonder - is there some way to
> figure out what is the clock speed of a particular CPU? maybe this way I
> can figure out whether my actions operate on both CPUs or only one one.

What are your Processor objects?  Here's a dual processor Xeon board with
a duplicated P_BLK.  The extra two objects are for the hyperthreading
logical CPUs.

IntelSE7501BR2.asl:        Processor (CPU1, 0x01, 0x00000410, 0x06) {}
IntelSE7501BR2.asl:        Processor (CPU2, 0x02, 0x00000410, 0x06) {}
IntelSE7501BR2.asl:        Processor (CPU3, 0x06, 0x00000410, 0x06) {}
IntelSE7501BR2.asl:        Processor (CPU4, 0x07, 0x00000410, 0x06) {}

No idea how to check clock speed of a particular CPU.  Try running a
benchmark pinned to one CPU and then the other.  I don't know the Linux
command for setting CPU affinity.  You could also run two tasks in
parallel that are a CPU benchmark.  Since throttling is linear, if you set
50% throttling and you get both tasks taking twice the time with
throttling as without, both CPUs are throttled.  If both tasks finish in
25% of the time, one processor is not throttled.

-Nate


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