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Bug 17707 - uptime, w, /proc/uptime; report wrong uptime
Summary: uptime, w, /proc/uptime; report wrong uptime
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: [OLD] Core system (show other bugs)
Hardware: x86 Linux
: High normal (vote)
Assignee: (DEPRECATED)
Depends on:
Reported: 2003-03-17 14:07 UTC by Johnny Withers
Modified: 2003-04-27 02:05 UTC (History)
0 users

See Also:
Package list:
Runtime testing required: ---

Possible reason (dummy.txt,21 bytes, text/plain)
2003-03-21 15:57 UTC, Gareth John

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Description Johnny Withers 2003-03-17 14:07:40 UTC
uptime/w reports an uptime of 5 days, however, login times date back almost 60 
days and some users have idle times of 8 days... 

Last boot:
reboot   system boot  2.4.20-gentoo-r1 Mon Jan 20 23:57         (55+12:43) 

current date:
Mon Mar 17 12:44:51 CST 2003

anti@void anti $ uptime;w;uname -a
 12:45:34 up 5 days, 19:39,  5 users,  load average: 0.00, 0.00, 0.00

 12:45:34 up 5 days, 19:39,  5 users,  load average: 0.00, 0.00, 0.00
root     vc/1      02Feb03  8days  0.03s  0.03s -bash
root     vc/2      29Jan03  8days  0.10s  0.10s -bash
anti     vc/3      08Mar03  8days  0.00s  0.00s -bash
anti     :0        02Feb03 ?xdm?  11:49m  0.02s -:0                 
anti     pts/0     12:30    0.00s  0.01s  0.00s w

Linux 2.4.20-gentoo-r1 #4 SMP Thu Jan 16 09:02:20 CST 2003 
i686 AMD Athlon(tm) MP 1600+ AuthenticAMD GNU/Linux

Reproducible: Didn't try
Steps to Reproduce:
1. boot gentoo system
2. wait ~50 days
3. run w and/or uptime

Actual Results:  
Nothing yet, i would imagine the same problem of a wrong uptime report.

Expected Results:  
Report the correct uptime.

Portage 2.0.46-r12 (default-x86-1.4, gcc-3.2.2, glibc-2.3.1-r3)
System uname: 2.4.20-gentoo-r1 i686 AMD Athlon(tm) MP 1600+
CONFIG_PROTECT="/etc /var/qmail/control /usr/kde/2/share/config /usr/kde/3/share
/config /usr/X11R6/lib/X11/xkb /usr/kde/3.1/share/config /usr/share/config"
CONFIG_PROTECT_MASK="/etc/gconf /etc/env.d"
USE="3dnow libg++ mikmod nls gtkhtml alsa slang bonobo guile imlib ldap aalib 
acpi als apache2 apm arts avi berkdb crypt cups dga dvd encode esd evo fbcon gd 
gdbm ggi gif gnome gpm gtk gtk2 imap innodb ipv6 java jikes jpeg kde libwww 
maildir mbox mmx motif mozilla mpeg mysql ncurses oggvorbis opengl oss pam 
pdflib perl pic png pnp python qt qtmt quicktime readline samba sdl spell sse 
ssl svga tcltk tcpd tiff truetype X xml2 xmms xv zlib x86"
CFLAGS="-march=athlon-xp -O3 -pipe"
CXXFLAGS="-march=athlon-xp -O3 -pipe"
FEATURES="sandbox ccache"
Comment 1 Gareth John 2003-03-21 15:57:54 UTC
Created attachment 9674 [details]
Possible reason

Have you changed the Jiffies setting in your kernel config? By default the
linux clock will wrap around every 490 days I believe. If you change the
Jiffies from the default 100 Hz to, say, 10 Hz the kernel clock will wrap at 49
days so after 49 days the uptime will reset to 0.

[ PS the attached file is empty - I wasn't sure how to get around Bugzilla
wanting me to attach a patch... ]
Comment 2 Johnny Withers 2003-03-21 19:35:26 UTC
I have no idea what Jiffies are. I greped my kernel.conf file (in /etc) for any word like this, nothing came up. Where should I go and check this?
Comment 3 Gareth John 2003-03-24 07:32:16 UTC
Kernel Jiffies can be found under: 

make menuconfig; 

Processor type and features->Set jiffies for i386 (HZ) (Multiple of 20); 

Mine is set to the default value of 100.
Comment 4 Johnny Withers 2003-03-24 09:35:43 UTC
This is all that is listed under "Processor type and features"
[*] Low latency scheduling
[ ] Control low latency with sysctl
(Pentium-III/Celeron(Coppermine)) Processor family
[*] Machine Check Exception
< > Toshiba Laptop support
< > Dell laptop support
< > /dev/cpu/microcode - Intel IA32 CPU microcode support
< > /dev/cpu/*/msr - Model-specific register support
<M> /dev/cpu/*/cpuid - CPU information support
(off) High Memory Support
(3GB) User address space size
[ ] Math emulation
[*] MTRR (Memory Type Range Register) support
[*] Symmetric multi-processing support
[*] Preemptible Kernel
[ ] Multiquad NUMA system
[ ] Unsynced TSC support

From /usr/src/linux/include/linux/version.h:
#define UTS_RELEASE "2.4.20-gentoo-r1"
#define LINUX_VERSION_CODE 132116
Comment 5 Jay Pfeifer (RETIRED) gentoo-dev 2003-04-27 02:05:49 UTC
this won't be fixed until 64-bit jiffies are added and i'm unsure if i'll include a backport from 
2.5 anytime soon, if ever.