Subject: Re: poor performances on cyrix 6x86
To: Manuel Bouyer <bouyer@ensta.fr>
From: Michael L. VanLoon -- HeadCandy.com <michaelv@HeadCandy.com>
List: port-i386
Date: 06/28/1996 10:30:21
>grefen@carpe.net said:

>> If the cyrix chip is probed a 486DLC  the caches are not enabled
>> in locore.s unless CYRIX_CACHE_WORKS and CYRIX_CACHE_REALLY_WORKS are enabled !!

>Well, the cyrix is probed as a i486DX, and not a 486DLC.
>However, I've tried to add options CYRIX_CACHE_WORKS,CYRIX_CACHE_REALLY_WORKS
>to my kernel config, but this didn't change anythings. 

You shouldn't mess with those unless you really have a 486DLC (fits in
a 386 motherboard; a 486DLC definitely is not a 6x86).

>We have also run the tests under Linux, the results are the same.

That's a good indication it's not NetBSD. ;-)

>However, this could really be a cache problem. Does anyone else have an idea ?

Yes, it could be a cache problem.  Have you tried talking it over with
your motherboard vendor?  Someone else just posted with cache problems
on an Intel motherboard that they're getting resolved.  Also, I have
heard of ASUS (and maybe some other) motherboards not working with
cheap no-name COAST modules.

>I think there sould be something to add to machep.c, or locore.s, to take
>full advantage of the 6x86.

No -- you should NOT need to mess with those.  It's supposed to be
100% Pentium compatible.  We should not need to add special code to
make it work.

-----------------------------------------------------------------------------
  Michael L. VanLoon                                 michaelv@HeadCandy.com
        --<  Free your mind and your machine -- NetBSD free un*x  >--
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