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Re: cpu scaling questions

On Mon, 2006-10-02 at 12:01 -0400, Dave Jones wrote:
> On Mon, Oct 02, 2006 at 09:45:27AM -0400, Thomas J. Baker wrote:
>  > 
>  > I've got two questions related to cpu scaling. On my laptop I've got a
>  > Core 2 Duo. Can the two cores scale frequencies independently?
> No. Think about it. You have a single package, with a single power source.
>  > Most of
>  > the time that doesn't seem like the case but every once in a while, my
>  > cpufreq applets show different speeds. I'm assuming that there is just a
>  > bit of slop involved and the two cores are always the same speed.
> It's a bug, but it should be cosmetic only. It's on the TODO, but
> there are a number of other issues in this code that need tackling
> first before it gets clean enough to fix this properly.
> FC6-update/FC7 stuff.
>  > On my desktop, I've got Xeon CPUs that support limited scaling; they run
>  > at either 2.8 or 3.4GHz. On FC5, they used to scale on demand but under
>  > FC6 they don't and the cpufreq applet has a manual setting for 2.8 or
>  > 3.4 with an automatic setting that is greyed out.
> Which cpufreq driver were they using ?
> File a kernel bug, and attach dmesg.
> 	Dave

Just curious - it must also a bug that under FC5, with two hyperthreaded
Xeon CPUs, all four logical processors scale independently?

I looked at my FC5 setup and had specified "DRIVER=acpi-cpufreq"
manually. Doing this for FC6 made the scaling behave like FC5,
automatically scaling up for load.


| Thomas Baker                                  email: tjb unh edu    |
| Systems Programmer                                                  |
| Research Computing Center                     voice: (603) 862-4490 |
| University of New Hampshire                     fax: (603) 862-1761 |
| 332 Morse Hall                                                      |
| Durham, NH 03824 USA              http://wintermute.sr.unh.edu/~tjb |

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