From: Thomas Renninger <trenn@suse.de>
To: Saru Addep <saru.dpm@gmail.com>
Cc: cpufreq@lists.linux.org.uk
Subject: Re: Overall picture of cpufreq..
Date: Sun, 13 Jan 2008 23:54:34 +0100 [thread overview]
Message-ID: <1200264884.4157.16.camel@queen> (raw)
In-Reply-To: <9f79f7f50801111415w354dc91fwfeec98b16a00fb74@mail.gmail.com>
On Fri, 2008-01-11 at 14:15 -0800, Saru Addep wrote:
> Hi All,
...
> 2) What is the purpose of userspace governor.
You can set the frequency from userspace:
/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
(or similar) pops up when you switch to userspace governor.
The first dynamic cpufreq approaches were done in userspace. You have a
daemon checking every some 100 ms for the CPU load (/proc/stats) and
then decide whether to increase or decrease the freq.
The ondemand governor is doing that in kernel, but has the sideeffect of
not supporting HW (IIRC speedstep-lib, possibly longhaul, powernow-k7
(not sure) and other older ones) that takes too long for switching
frequencies. Then you would still need the userspace governor for
switching.
Thomas
next prev parent reply other threads:[~2008-01-13 22:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-11 22:15 Overall picture of cpufreq Saru Addep
2008-01-11 22:50 ` Leisner, Martin
2008-01-13 22:54 ` Thomas Renninger [this message]
2008-01-14 2:12 ` Saru Addep
2008-01-14 7:08 ` Tomasz Chmielewski
2008-01-14 7:51 ` Saru Addep
2008-01-14 9:51 ` Thomas Renninger
2008-01-14 10:16 ` Tomasz Chmielewski
2008-01-14 10:32 ` Thomas Renninger
2008-01-14 10:59 ` Tomasz Chmielewski
2008-01-14 19:13 ` Saru Addep
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=1200264884.4157.16.camel@queen \
--to=trenn@suse.de \
--cc=cpufreq@lists.linux.org.uk \
--cc=saru.dpm@gmail.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.