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

Myles Watson mylesgw at gmail.com
Tue Jul 21 14:25:38 CEST 2009

> Following up on this - Patrick helped in IRC this evening, and we came to
> the
> conclusion that it's probably *not* an MTRR issue, since we figured out
> the
> code seems to set MTRRs properly.
I wonder what else could cause it to be so slow?  It's especially surprising
for the memset, which is pretty simple.  Does it use movnti for that?

> 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?

I guess I would:
1. Add some little benchmark loops reading/writing different areas
	a. read ROM & time it
	b. read from RAM (cached area) and time it
	c. read from RAM (non-cached area)
	d. write to RAM (cached area)
2. disable MTRRs to see if it would go even slower.

Sorry that's not much help, but I don't have a fam10 box to try things on.


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