Kevin Oberman wrote:
Date: Tue, 9 Aug 2005 11:35:29 +0200
From: Bruno Ducrot <[EMAIL PROTECTED]>
Sender: [EMAIL PROTECTED]
On Tue, Aug 02, 2005 at 12:22:02AM +0200, Tijl Coosemans wrote:
A couple days ago I updated my system and was excited to see cpufreq
and powerd in 5-stable. Since then however I noticed that my laptop
temperature is about 5°C higher than with est and estctrl. I found that
cpufreq when setting 200MHz for example set the absolute frequency to
1600MHz (max for this laptop) and the relative frequency (p4tcc) to
12.5% instead of using a more power conserving setting like 800MHz/25%.
The problem is that cpufreq_expand_set() (sys/kern/kern_cpu.c)
traverses freq levels from high to low when adding relative levels and
skips duplicates. When it wants to add 800MHz/25% it sees this setting
as a duplicate of 1600MHz/12.5% it has found before. This can be fixed
by letting cpufreq_expand_set() traverse freq levels in reverse order
(and still skipping duplicates). Then each frequency level has the
lowest possible absolute setting. This is a one line change in
sys/kern/kern_cpu.c (line 653).
It's a well known bug. Someday I think I will have enough time to fix
that one if Nate don't bite me.
I have been running with Tijl's patch set for several days with great
results. Testing has shown that the patches resolve both issues and I
now see only 11 CPU speeds, all of those below the lower CPU clock speed
are at that lower speed. Thus far I have seen no negative issues. The
temperature of my system is noticeably cooler when not running something
that is compute intensive.
I'm working on reviewing and perhaps rewriting some of the patches.
They may work fine but there are some subtle issues, for instance, with
future systems that support more than one relative driver. The goals
are correct but the implementation needs a little work.
--
Nate
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