Re: Machines misreporting Bogomips

[Matthew Dharm <mdharm-kernel@one-eyed-alien.net>]

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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

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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-- 
Matthew Dharm                              Home: mdharm-usb@one-eyed-alien.net 
Maintainer, Linux USB Mass Storage Driver

G:   Baaap booop BAHHHP.
Mir: 9600 Baud?
Mik: No, no!  9600 goes baap booop, not booop bahhhp!
					-- Greg, Miranda and Mike
User Friendly, 12/31/1998

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