Re: [tlug] Tweaking the kernel

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

Jonathan Byrne wrote:

> On Thu, Jun 19, 2003 at 05:48:33PM +0900, Dan Lindfield wrote:
>
>> cat /proc/cpuinfo reveals amongst other things a 'cache size :64 KB'
>> I actually have 512KB, this must have an effect on machine speed!
>
>
> Actually, cpuinfo is correct, a K62 has either 32K or 64K of
> L1 cache. The 512K figure is for your L2 cache.


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. If I do 'cat
/proc/cpuinfo' on this machine I get 'cache size : 256 KB' which seems
to refer to the L2 cache.

> MTRR settings can be used for tweaking performance through
> things such as write-combining and I've read (but haven't
> tried it myself) that it's sometimes possible to give video
> performance - esp. for gaming - a real boost this way.
> Google for more on that if you're interested.

I've Googled quite a bit but no good leads so far. I'll continue to
persevear with the clues you've given me above.

> However, AFAIK it's not possible to lie to the OS about your
> L1 or L2 cache sizes by manipulating /proc/cpuinfo or MTRRs,
> not would it likely do anything good if you could do so. 


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)?

Thanks again for you comments.

Dan