Bug 180306 – gentoo-sources-2.6.21-r2 reports unbelievable CPU scaling frequencies

• Status: RESOLVED NEEDINFO
• Product: Gentoo Linux

[Description Joshua Hoblitt 2007-05-30 01:30:39 UTC]

Please see the attached text from /proc/cpuinfo & /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies for 2.6.17-gentoo-r4 and 2.6.21-gentoo-r2.  I suppose it's possible that 2.6.21 has unlocked a lower p-state but I'm having trouble believing 349.991MHz is a real value as my 2GHz pentium-M laptop only steps down to 800Mhz.  What's even weirder is that the system seems to be scaling it's CPU freq reasonably under load.

cat /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state 
349991 432298
699982 300
1049973 100
1399965 200
1749956 100
2099947 300
2449938 0
2799930 9225


Reproducible: Always




Portage 2.1.2.7 (default-linux/x86/2007.0, gcc-3.4.6, glibc-2.5-r2, 2.6.21-gentoo-r2 i686)
=================================================================
System uname: 2.6.21-gentoo-r2 i686 Intel(R) Xeon(TM) CPU 2.80GHz
Gentoo Base System release 1.12.9
Timestamp of tree: Tue, 29 May 2007 18:00:01 +0000
distcc 2.18.3 i686-pc-linux-gnu (protocols 1 and 2) (default port 3632) [disabled]
ccache version 2.4 [disabled]
dev-java/java-config: 1.3.7, 2.0.31-r5
dev-lang/python:     2.3.5-r3, 2.4.4-r4
dev-python/pycrypto: 2.0.1-r5
dev-util/ccache:     2.4-r7
sys-apps/sandbox:    1.2.17
sys-devel/autoconf:  2.13, 2.61
sys-devel/automake:  1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2, 1.10
sys-devel/binutils:  2.17
sys-devel/gcc-config: 1.3.16
sys-devel/libtool:   1.5.22
virtual/os-headers:  2.6.17-r2
ACCEPT_KEYWORDS="x86"
AUTOCLEAN="yes"
CBUILD="i686-pc-linux-gnu"
CFLAGS="-O2 -march=pentium4 -pipe"
CHOST="i686-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/kde/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/lib/mozilla/defaults/pref /usr/share/X11/xkb /usr/share/config"
CONFIG_PROTECT_MASK="/etc/env.d /etc/env.d/java/ /etc/gconf /etc/init.d /etc/java-config/vms/ /etc/revdep-rebuild /etc/terminfo /etc/texmf/web2c"
CXXFLAGS="-O2 -march=pentium4 -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="distlocks metadata-transfer sandbox sfperms strict"
GENTOO_MIRRORS="http://distfiles.gentoo.org http://distro.ibiblio.org/pub/linux/distributions/gentoo"
MAKEOPTS="-j3"
PKGDIR="/usr/portage/packages"
PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --delete-after --stats --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --filter=H_**/files/digest-*"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
PORTDIR_OVERLAY="/usr/local/portage"
SYNC="rsync://gentoo.ifa.hawaii.edu/gentoo-portage"
USE="acl acpi alsa apache2 bash-completion berkdb bitmap-fonts cdr cli cracklib crypt cups dri dvdr firefox fortran gdbm gnome2 gnu gpm gtk2 hal ic iconv imap ipv6 isdnlog ithreads ldap libg++ mbox midi mudflap ncurses new-login nls nptl nptlonly openmp p pam pcre perl pppd python readline reflection session spl ssl sysfs tcpd tils truetype-fonts type1-fonts unicode x86 xinerama xorg zlib" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1 emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mulaw multi null plug rate route share shm softvol" ELIBC="glibc" INPUT_DEVICES="keyboard mouse evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" USERLAND="GNU" VIDEO_CARDS="mach64"
Unset:  CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LANG, LC_ALL, LDFLAGS, LINGUAS, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS

[Comment 1 Joshua Hoblitt 2007-05-30 01:31:11 UTC]

Created attachment 120670 [details]
2.6.17 info

[Comment 2 Joshua Hoblitt 2007-05-30 01:31:36 UTC]

Created attachment 120672 [details]
2.6.21 info

[Comment 3 Daniel Drake (RETIRED) 2007-06-09 15:29:23 UTC]

Please compile your 2.6.21 kernel with cpufreq debugging support, then boot with "cpufreq.debug=3" and attach dmesg here. Please also attach your kernel .config

[Comment 4 Daniel Drake (RETIRED) 2007-06-29 01:42:58 UTC]

see comment #3

[Comment 5 Joshua Hoblitt 2007-07-19 04:38:24 UTC]

This issue persists with 2.6.22-gentoo-r1.

[Comment 6 Joshua Hoblitt 2007-07-19 04:38:54 UTC]

Created attachment 125305 [details]
2.6.22-gentoo-r1 cpufreq.debug=3 dmesg

[Comment 7 Joshua Hoblitt 2007-07-19 04:39:32 UTC]

Created attachment 125307 [details]
2.6.22-gentoo-r1 config

[Comment 8 Joshua Hoblitt 2007-07-19 04:41:24 UTC]

I'm reopening this bug as the requested information has been provided (sorry about the delay).

[Comment 9 Daniel Drake (RETIRED) 2007-07-22 04:32:14 UTC]

Created attachment 125612 [details, diff]
patch

If you apply this patch to 2.6.21, do the frequencies become more "believable"?

[Comment 10 Daniel Drake (RETIRED) 2007-08-05 22:18:11 UTC]

see comment #9

If that patch does "help", it confirms my suspicion that your xeon can actually clock to those lower frequencies. Here's why they weren't available for some time: http://lkml.org/lkml/2006/10/28/148