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List:       linux-smp
Subject:    Re: Bogomips and MMX was (Re: RedHat 5.0 + Tomcat + Intel  166Mhz MMX)
From:       "Manfred Brands" <m.brands () fugro-intersite ! nl>
Date:       1997-12-19 16:28:13
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I lost about 50 BogoMips, by changing an option in the same kernel.
It all depends on alignment of the 'bogo-mips' loop.
Whether it is aligned on a 'cache' line or not.

There is a patch at Big Mama (http://www.huwig.de/linux/mama)
which aligns the loop at 16 bytes to give a consistent number for the
same processor.

The difference between MMX and non-MMX is Intel's bigger level-1 cache
and jump prediction.

Manfred.
----------
> From: Kimmo Laine <kl2398@turkuamk.fi>
> To: Chris Pirih <proverbs@wolfenet.com>
> Cc: linux-smp@vger.rutgers.edu
> Subject: Re: Bogomips and MMX was (Re: RedHat 5.0 + Tomcat + Intel  166Mhz MMX)
> Date: Friday, 19 December, 1997 11:53
> 
> 
>   Earlier I send those result ... that was with kernel 2.0.32 .. I
> compiled new one from 2.0.33 source and here are those results
> 
> >cat /proc/cpuinfo
> processor       : 0
> cpu             : 586
> model           : 4
> vendor_id       : GenuineIntel
> stepping        : 3
> fdiv_bug        : no
> hlt_bug         : no
> f00f_bug        : yes
> fpu             : yes
> fpu_exception   : yes
> cpuid           : yes
> wp              : yes
> flags           : fpu vme de pse tsc msr mce cx8 apic mmx
> bogomips        : 330.96
> 
> processor       : 1
> cpu             : 586
> model           : 4
> vendor_id       : GenuineIntel
> stepping        : 3
> fdiv_bug        : no
> hlt_bug         : no
> f00f_bug        : yes
> fpu             : yes
> fpu_exception   : yes
> cpuid           : yes
> wp              : yes
> flags           : fpu vme de pse tsc msr mce cx8 apic mmx
> bogomips        : 330.96                                          
> 
> 
>   It has came something like 100 more bogomips. How the hell to analyze
> these figures ? and what REALLY has happened ?
> 
> 
>              ****                 Kimmo Laine              ****
>              ****          kimmo.laine@turkuamk.fi         ****
>            
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