Subject: Re: Bogomips, WAS Re: wlan-ng fix?
From: Jim Gribbin (jewelrysupplier@gci.net)
Date: Mon Mar 03 2003 - 12:45:53 AKST
Well, maybe I just hadn't figured out the register tweaks using set6x86
then. I do know that my laptop with debian and the 2.4bf kernel wasn't
running X as crisply as Lief's p133 laptop, also w/ 80 MB ram. I'm not
sure it is with the 2.2 kernel either, but it is noticeably better.
It might also be that that kernel had to much stuff running that I
didn't need. I didn't spend much time tweaking the kernel.
I do seem to have the power consumption down though. It was running
hotter and periodically restarting while connected to the battery
charger. I don't think it was keeping up. I can get about an hour out of
it on battery now - even with a bad battery.
Jim Gribbin
On Mon, 2003-03-03 at 05:45, Christopher E. Brown wrote:
> On 3 Mar 2003, Jim Gribbin wrote:
>
> > BTW - I was comparing notes with a couple of people about laptops Fri
> > evening. It seems that my problems with th 2.4 kernel may be unique to
> > my laptop. It's running a Cyrix MediaGX 180 MHz that I didn't think
> > should be that different than any other sub-200MHz pentium, but it seems
> > it is. Runs at 60 BogoMips instead of the 360 I would expect if it were
> > a real pentium. This doesn't change the fact that the 2.4 kernel is not
> > required for linux-wlan-ng. I currently have it running on the 2.2.16 RH
> > kernel w/ pcmcia-3.1.19.
>
> Ahh, but the MediaGX *is not* a pentium. I supports most i586 ops and
> some i686 ops but is in no way the same CPU design. BogoMIPS are just
> that BOGUS MIPS. They measure how many million times a second the CPU
> runs a *specific* timing loop, and is used to calibrate a few things.
> Bogos are comparable only between 2 of the exact same CPU (arch and
> submodel), and only running the same kernel (I main exact same file
> copied to two systems).
>
>
> So if you had an Athlon XP 1700+ and a 2200+ both booting the same
> kernel (single file copied to both systems) you could get a meaningful
> comparison of their relative speed at running a small useless timing
> loop. Any changes to this (different kernel versions, different
> compile options, different compilers, diff CPU types) will throw the
> comparison off, sometimes by a little, sometimes in a very big way.
> (In the past there have been several major changes to the timing loop
> code to better reflect what they are calibrating. If you compared say
> an AMD 486DX4-133 booting 1.2.13 and 2.4 the bogos should be (IIRC)
> about 2.5 times higher with 2.4 than 1.2.13. IIRC there were major
> changes both in the 1.2.x -> 2.0.x and 2.0.x -> 2.2.x made to the
> loop.
>
>
> An abnormally low bogo rating is something to look into (for example
> if you change a memory related option is BIOS and it drops 40 points,
> look into it. Otherwise, ignore it. The MediaGX usually sees a
> rating approx the same as its external bux speed (it has lousy
> internals), for example a MediaGX 233Mhz STB I have shows 60something
> Bogos with 2.4 (66Mhz CPU bus). This means almost nothing though, a
> MediaGX 233 performs about like a Pentium MMX 180Mhz for real work
> loads, it just sucks are running an extremely small code loop (it
> takes a GX 3 - 4 clock cycles to run one loop, where and Athlon-XP
> does a few optomizations and runs 2 complete loops *per* clock cycle),
> and kernels/userspace almost never fall into this class.
>
> --
> I route, therefore you are.
>
>
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