Re: Machines misreporting Bogomips

From: Roger Larsson (roger.larsson@norran.net)
Date: Thu Jan 31 2002 - 18:30:48 EST


On Fridayen den 1 February 2002 00.21, Matthew Dharm wrote:
> I don't know if this will help much, but I have seen that type of
> performance drop on systems when the entire cache is disabled.
>
> Matt

>From the report below...
> > cache size : 0 KB

/RogerL

>
> On Thu, Jan 31, 2002 at 05:55:57PM -0500, Greg Boyce wrote:
> > 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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-- 
Roger Larsson
Skellefteċ
Sweden
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