From: Wes Felter <wesley@felter.org>
To: linux-kernel@vger.kernel.org
Subject: Re: HELP: cpufreq on HT and/or SMP systems
Date: Fri, 01 Aug 2003 17:36:21 -0500 [thread overview]
Message-ID: <pan.2003.08.01.22.36.19.940443@felter.org> (raw)
In-Reply-To: 200307312353.54735.gallir@uib.es
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/
next prev parent reply other threads:[~2003-08-01 22:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-31 21:53 HELP: cpufreq on HT and/or SMP systems Ricardo Galli
2003-08-01 22:36 ` Wes Felter [this message]
2003-08-01 22:51 ` Xavier Bestel
2003-08-01 23:01 ` Wes Felter
2003-08-05 11:16 ` Pavel Machek
2003-08-06 8:10 ` Dominik Brodowski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=pan.2003.08.01.22.36.19.940443@felter.org \
--to=wesley@felter.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox