Machines misreporting Bogomips

From: Greg Boyce (gboyce@rakis.net)
Date: Thu Jan 31 2002 - 17:55:57 EST


kernel folk,

I've got a strange issue that I've been struggling to find the solution to
for some time now.

I work in a group that assists in the managing of large numbers of
deployed linux boxes running variants of the 2.2 kernel on them. The
machines themselves are all pretty standard. There are slight variances
on vendors, cpu speeds, etc., but they're all running from the same
motherboards.

Every once in a while we come across single machines which are running a
lot slower than they should be, and are misreporting their speed in
bogomips under /proc/cpuinfo. Reinstalling the OS and changing versions
of the kernel don't appear to affect the machines themselves at all.

I was wondering if anyone would be able to provide me with a starting
point to hunt this down. The only solution we had found in the past was
to replace the machines, but some of them are located out of the country
and that would be expensive.

Here is the output from /proc/cpuinfo for machines. The first machine is
normal, the second is affected by this bug. They're both running the same
hardware, although the first machine's CPU is 650mhz instead of 500mhz.

Machine 1:
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 8
model name : Pentium III (Coppermine)
stepping : 3
cpu MHz : 645.676332
cache size : 0 KB
fdiv_bug : no
hlt_bug : no
sep_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 3
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
cmov pat pse36 psn mmx osfxsr kni
bogomips : 643.89

Machine 2:
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 7
model name : Pentium III (Katmai)
stepping : 3
cpu MHz : 496.677416
cache size : 512 KB
fdiv_bug : no
hlt_bug : no
sep_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
cmov pat pse36 mmx osfxsr kni
bogomips : 4.06

Let me know if there's anything else I can provide to help with the
diagnosis. The machine itself is an IBM Netfinity 4000R.

--
Gregory Boyce

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