lkml.org 
[lkml]   [2003]   [Aug]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: HELP: cpufreq on HT and/or SMP systems
Date
On Thu, 31 Jul 2003 23:53:54 +0200, Ricardo Galli wrote:

> I have some doubts regarding cpufreq for SMP systems (for developing
> http://mnm.uib.es/~gallir/cpudyn/).
>
> If I remember well, I read a while ago that cpufreq didn't work in SMP
> systems, but reading the docs and kernel/cpufreq.c, it seems there should be
> any problem?
>
> Is it true?
>
> OTH, I trying it on a P4 HT, and it works, changes in the frequency of one of
> the "cpu's", changes both.

That makes sense, since the CPU only has one clock.

> What happens in the case of several real cpu's? Does it keep the same
> frequency for every cpu? According to a comment in cpufreq.c, it seems that
> each cpu might have different frequencies.

AFAIK no SMP systems have voltage/frequency scaling (SpeedStep/PowerNow).
I've heard that ACPI P-states works on SMP, but if it's not doing
voltage/frequency scaling then I don't know what it's doing.

Wes Felter - wesley@felter.org - http://felter.org/wesley/

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:47    [W:0.074 / U:0.304 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site