Re: [tlug] Tweaking the kernel

[Dan Lindfield <dan.lindfield@example.com>]

Jonathan,

This is getting very interesting. The cause of my frustration with the
notebook's speed under MDK9.1 is that I have 256Mb of RAM backed by
512Kb of L2 cache. Both of which should ensure good performance (When I
purchased the Notebook 4 years ago I primarily wanted to use it for
running CAD software (Pro-Engineer) and CFD software both of which are
memory thirsty, under Windows 98 speed was not an issue with this
software). The speed issue is evident from boot as it takes 3 minutes
to boot the system and 2 minutes to load KDE. Does this point to a non
KDE problem?

Anyway, thanks for the web site
"http://www.penguin.cz/~stano/en/mtrr.html" pointer, it is a very
interesting read. It gives a very good example on how to use mtrr and
might have given me further insite into the root of my problems:

cat /proc/mtrr on my system returned:

reg00: base=0xfb800000 (4024MB), size=   4MB: write-combining, count=1

There is only this one line and the above referenced web page suggests:

• For example, the output for a machine with 96 MB of memory the output is

    reg00: base=0x00000000 (   0MB), size=  64MB: write-back, count=1
    reg01: base=0x04000000 (  64MB), size=  32MB: write-back, count=1

I must therefore note:

1. My /proc/mtrr does not reflect the 256Mb of RAM that my system has.

2. My /proc/mtrr points to my VGA compatible controller Trident
Cyberblade and has 4Mb of memory allocated to it when in fact it should
have 8Mb.

At this stage I'm not sure this is important or not and I need to
investigate further.


To answer some of your additional questions: I have infact recompiled
the Kernel to use the AMD-K6 2/3 CPU with the additional mtrr support.
I have not included the 'AMD K6 Power Now Module' as this is supposed
to manage a CPU slowdown to conserve battery power, I couldn't face
working any slower!
I do work under KDE and unfortunately I'm also a fan of Mozilla (It is
a dinosaur in more than just its name!). I've wanted to explore Icewin
before, maybe now is the time to look into it.

Well, thanks again,

Dan


Jonathan Byrne wrote:
> On
> Thu, Jun 19, 2003 at 07:00:02PM +0900, Dan Lindfield wrote: 
>   
> > Thanks but I'm now even more confused, I also
> > have a PC using an AMD 
> > XP1800+ CPU and is loaded with Mandrake 9.1. My understanding is that 
> > the XP1800 has 128KB of L1 cache and 256KB of L2 cache. 
> >   
>   
> Hmm, good point.  That led me to go looking for documentation of 
> exactly what /proc/cpuinfo does to get that cache number, but 
> I have found nothing right.  A read of the kernel source may be 
> the documentation for that.  I know some people I can ask. 
>   
> As Tobias mentions, perhaps it's just reporting the larger of 
> the two cache sizes.  I got the same report on my Athlon 
> 2200+.  It would be nice if it would report either L1,L2 or 
> a unified total. 
>   
> This is a good piece on mtrr, although not specific to the 
> K62: 
>   
> http://www.penguin.cz/~stano/en/mtrr.html 
>   
> > Does that mean I'm stuck with what I've got?
> > Is my only option to 
> > improve speed to cut down on any services running in the background
> > (I'm 
> > not looking at gaming)? 
> >   
>   
> I don't think the system processes will make much difference to
> performance, although for security reasons you shouldn't run anything 
> you don't need. 
>   
> A K62-400 running as a web server could saturate a T3, all it needs 
> is memory. 
>   
> Speaking of memory, how much of it do you have?  Insufficient memory 
> is the biggest single problem with performance on pretty much any 
> system.  If your notebook has only 32 or 64 meg, bump that to 128 
> and you'll see a big performance boost. 
>   
> Are you running KDE or Gnome on it?  If so, chucking that and moving 
> to a faster, lighter environment would help a lot.  I hear a lot 
> of good things about IceWM and Fluxbox.  Gnome and KDE both add a 
> lot of their own overhead. 
>   
> Recompiling everything optimized for the K62 could help also.  A 
> large undertaking to be sure, but can help you ring extra peformance 
> out of it.  If you go this way, moving from Mandrake to Gentoo would 
> probably be a worthwhile move. 
>   
> Also, keep in mind that a notebook old enough to have a K62 probably 
> has a slow disk and lackluster video.  I used to use a Toshiba with 
> a K62-350 and it was fairly slow, but had 192 meg of memory, so that 
> kept it moving even when running XP (Linux was not an option b/c 
> nothing I tried - BSD included - could deal with the spastic cardbus 
> controller on that machine; only Windows worked, everything else 
> hung during the install). 
>   
> Jonatha
> n