Re: bogomips
Subject: Re: bogomips
Date: Fri, Nov 13, 1998 at 07:27:12AM -0600
>
> I remember back in '98 when wtopa@ix.netcom.com wrote:
> > Yes. 2.0.34/35 on Slackware 149.9. On debian 2.0.34 120 Bogomips and
> > on 2.0.35 130.6. The .config's on both dists are the same as well.
> > Interesting, isn't it. NOT!
> <...>
> >
> > Would appreciate it if anyone could give me some reason for the
> > difference in the Debian kernel.
>
> As someone mentioned, it could be that there are some patches in the
> Debian kernel, not in the slackware. Realize that Bogomips are
> really sensative to alignment in memory, if the loop is in the wrong
> place it could change the numbers. Also you could be using
> different versions of the C compiler on the different machines.
> try typing gcc --version on both.
>
> gcc 2.7.2.x is the official compiler for the linux kernel, at least in
> Linus' mind. There have been on-and-off report of breakage with
> gcc 2.8.x and (especially) egcc. Go look on linux-kernel for
> anything by Linux with egcc in the subject line for more info..
>
> Matt
Matt may have found the link. I just went to the 3 dists and got the
following:
Debian slink %gcc --version gcc 2.7.2.3
Slackware 3.3 %gcc --version gcc-2.7.2.2
Slackware 3.5 %gcc --version egcs-2.9.29 980515 egcs 1.0.3
NOTE: Debian uses glibc while Slackware is still using libc.
So I got the source for gcc-2.7.2.3 and compiled it for the Slack3.3 dist.
(Yea, I know, I have too much spare time!) I installed the new version
(%gcc --version gcc-2.7.2.3 ), and recompilied linux-2.0.35. and
rebooted.
Slackware _again_ reports BogoMips at 149.91, now with kernel compiled
with gcc-2.7.2.3. So that doesn't look like it is/was the cause.
Now I will take the kernel source from ftp.kernel.org for 2.0.35 and
compile it on Debian with make dep,clean and zImage, make a boot
floppy and see if that changes anything.
No, it didn't. Debian still says that BogoMips = 130.66. So that
leads me to believe the kernel-source.deb files are ok, so is
gcc-2.7.2.3. Leaves glibc. That I will not change!
OK, someone said that the BogoMips are meaningless. It just might be
that he is correct. I have just noticed something I hadn't found
before. I have saytime running in cron and it reports the time on the
hour. On Slackware (149.91 Bogomips) the time is "the hour and 1
sec", on Debian (130.66 BogoMips) the time is "the hour exactly"!
Well I had fun tracking this down but, to me anyway, BogoMips is a
nice number but I won't lose any sleep over differences between
distributions.
Hope this answers my question? Or does it???
Wayne
> --
> /* Matt Sayler -- mpsayler@zen.as.utexas.edu -- atwork?astronomy:cs
> http://www.cs.utexas.edu/users/mpsayler -- (512)471-7450
> Have you ever imagined a world with no hypothetical situations? */
>
--
If you put garbage in a computer nothing comes out but garbage. But
this garbage, having passed through a very expensive machine, is
somehow enobled and none dare criticize it.
_______________________________________________________
Wayne T. Topa <wtopa@ix.netcom.com>
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