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 DriverG: 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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