"Prophete J. Charles" wrote:
>
> I am using a dual Pentium machine with two P133 (oc to
> P166) CPUs and RedHat Linux 6.2 compiled for smp
> support. I wanted to ask about this strange
> bogomips number I have been getting. For cpu0 I get
> 66.36 BogoMips which is in the expected range for a
> P166. However, for cpu1 I get 53.04 BogoMips which is
> in the range of a P133. Does anyone find this strange?
As I told an earlier questioner, the BogoMIPS number should not concern
you. One CPU is not running significantly slower than the other. The
word "Bogo" appears in BogoMIPS for a very good reason: the number is
bogus.
I've noticed that overclocked Pentiums tend to not get the same
BogoMIPS. This is particularly common on the Supermicro dual-slot
boards. Try swapping the CPUs in their positions. I'd wager you'll find
that it is the position of the CPU that makes the difference; that is,
the second CPU will always be the one that has lower BogoMIPS.
In an effort to further convince you that BogoMIPS is b*llsh*t and
should not be cared about, take my /proc/cpuinfo as a striking example:
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 6
model name : Celeron (Mendocino)
stepping : 5
cpu MHz : 561.105
cache size : 128 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 fxsr
bogomips : 1120.67
processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 6
model name : Celeron (Mendocino)
stepping : 5
cpu MHz : 561.105
cache size : 128 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 fxsr
bogomips : 1120.67
This is on an ABIT BP-6 with 400 MHz Celerons clocked to 560 MHz
(rock-solid with no outrageous cooling required -- with a little extra
cool air these CPUs will do fine at 600 MHz).
Notice the 1120.67 BogoMIPS. Not only is this number HIGHLY dependent on
the kernel version I am using, it sometimes (although rarely) changes
from boot to boot with the same kernel. If, like you say, 53 BM is
equivalent to 133 MHz, then (punch calculator) my CPUs are cooking along
at a nice 2.8 gigahertz each for a total computing capacity of 5.6
gigahertz. Obviously if this were true I would be busy rendering frames
for the next big Pixar movie for $100 a piece.
BogoMIPS is a complicated interaction between the kernel, motherboard,
memory caches, main RAM, and CPUs. It is not a performance benchmark.
Regards,
Scott
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