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Subject[NOT_A_BUG] (I think) MTRR nice things... :)
Hi all,

I was trying to x11perf(1) measure the performance boost of my ATI
rage IIC with and without the mtrr aperture

(0)pern:~/tmp% cat /proc/mtrr
reg00: base=0x00000000 ( 0MB), size= 64MB: write-back, count=1
reg01: base=0xaf000000 (2800MB), size= 2MB: write-combining, count=2

and I did a typing error resulting in reg00 (main memory) being
deleted. Try to guess what happened. System was _really_slow_, much
less than my old 386sx. You could notice almost one second wait
between prompts of shell (bash on vesafb console).

Well. I think this is a "so do not do it" thing, but I was really
amazed to see such a _big_ slowdown. Really cache/no cache can do this
difference?

Romano



--
Romano Giannetti, Professor - Univ. Pontificia Comillas (Madrid, Spain)
Electronic Engineer - phone +34 915 422 800 ext 2410 fax +34 915 596 569

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