Re: Cyrix anyone?

Barnabas Wolf (barnabas@barnabas.port.net)
Mon, 25 Mar 1996 04:18:53 -0500


> > > I am running linux on the 120Mhz Cyrix-6x86 (P150+). THe Cyrix gives
> > > me bogomips of 119.6 which about reflects the 4-5x speedup I see
> > > compared to my old 486dx2-66. (Sorry I have no Pentiums to compare it
> > > to.) The compilation of a kernel setup whose final zImage is ~500k
> > > (compiled with "make dep clean zImage") takes ~11 minutes on the
> > > otherwise mostly idle system with 32Mb ram and no swap.
> >
> > My Pentium-166 with 32Mb EDO and 512kb PB cache gets 66.15 BogoMips
> > and does 'make dep clean zlilo modules modules_install' in under
> > 10 minutes (approx 9:30).
> >
> > I think this shows how BOGUS BogoMips are :-)
> >
>
> Though comparing kernel compile times is just as bogus... Specially if
> you omit important stuff like if you have SCSI or not, etc....
>
> Just for an example.. I just timed the compile of a 2.0 kernel on
> my Pentium 90 and got it done in about 8 minutes... (36.04 Bogo MIPS)
>
> So something MUST be wrong with your Pentium 166 :) :)
>
> (Just as a note, this was without Network, aout support, or any other
> file systems but ext2... bootable, but not especially usefull :))
>
> Ben

Right, however I did mention the kernel size. While it might lacks
exact 1-1 mapping with the compile time, it's close --- and
without a detailed list of options.

A bare kernel you described compiles into a 225K image here.

500 / 225 = 2.2 ---> ratio of kernel sizes
8 * 2.2 = 17.6 ---> assumimg linear relationship between compile time
and kernel size, you would get 17-18 minutes for a
kernel whose image is 500k
17.6 / 11 = 1.6 ---> the compile times differ by a factor of 1.6
150 / 90 = 1.66 ---> the cpu speeds (150P+ cyrix and P90) differ by a
factor of 1.66

As you can see they are withing 5% of each other (which you might
expect if the P rating is correct?)

barnabas