[coreboot] solved - Re: fam10/h8dmr: extreme slowness in CBFS memset /memcpy

[Ward Vandewege]

On Tue, Jul 21, 2009 at 08:23:22AM -0600, Myles Watson wrote:
> > It's actually just a plain byte-by-byte assignment in c, see
> > src/lib/memset.c.
> It would be interesting to see if you make it 4 bytes at a time if it is 4x
> faster.
> 
> > > > We found out after adding an extra MTRR over the flash chip, which did
> > not
> > > > change anything.
> > >
> > > Did you disable and re-enable the cache so that the settings take
> > effect?
> > 
> > Hmm, we tried adding it here
> > 
> >   src/cpu/amd/car/clear_init_ram.c
> > 
> > in function set_init_ram_access, which already sets an mtrr.
> I always wondered about that one.
> 
> The thing that makes it hard to debug is that it will read back correctly
> even if it hasn't taken effect.
> 
> > Thanks - will see if I can try some of these things.
> Good luck,

So - you're not going to believe this. Compiler issue. I was compiling with
gcc (Ubuntu 4.3.3-5ubuntu4) 4.3.3 on 32 bit. 

I noticed that about one in every 10 burn/boot cycles or so, the slowness
would not be there.

So I switched back to gcc-3.4 (GCC) 3.4.6 (Ubuntu 3.4.6-8ubuntu2) on 32 bit,
and it's gone altogether, every time.

Is anyone else using gcc 4.3 (32 bit) to compile coreboot?

Thanks!
Ward.

-- 
Ward Vandewege <ward at gnu.org>