From: Riccardo Vestrini <riccardov@sssup.it>
To: linux-laptop@vger.kernel.org
Subject: is it really better speedstep-ich vs. p4-clockmod cpufreq driver?
Date: Thu, 22 Jul 2004 11:28:30 +0200 [thread overview]
Message-ID: <40FF88BE.2090507@sssup.it> (raw)
it seems that speedstep-ich and acpi cpufreq driver have only two usable
clock frequencies, while p4-clockmod has eight
my cpu is: Intel Mobile Intel(R) Pentium(R) 4 CPU 3.06GHz stepping 09
last 2.6 kernel I tried (2.6.7) has introduced a warning while loading
p4-clockmod module:
p4-clockmod: P4/Xeon(TM) CPU On-Demand Clock Modulation available
p4-clockmod: Warning: Pentium 4-M detected. The speedstep-ich or acpi
cpufreq modules offer voltage scaling in addition of frequency scaling.
You should use either one instead of p4-clockmod, if possible.
so I immediatly switched to speedstep-ich discovering that:
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
3066590 1599960
while with p4-clockmod I have:
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
383323 766647 1149971 1533295 1916618 2299942 2683266 3066590
using acpi driver gives a message:
cpufreq: CPU0 - ACPI performance management activated.
cpufreq: P0: 3059 MHz, 24000 mW, 100 uS
cpufreq: *P1: 1596 MHz, 12000 mW, 100 uS
but:
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
3059000 1596000
so, what driver is supposed to be better? and why speedstep-ich driver
has only two frequencies?
--
Riccardo Vestrini
<riccardov@sssup.it>
"Computers are good at following instructions,
but not at reading your mind." - D. E. Knuth, The TeXbook
next reply other threads:[~2004-07-22 9:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-22 9:28 Riccardo Vestrini [this message]
2004-07-22 16:20 ` is it really better speedstep-ich vs. p4-clockmod cpufreq driver? Jim Carter
2004-07-22 23:10 ` Riccardo Vestrini
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