From: Matan Ziv-Av (zivav@CS.bgu.ac.il)
Date: Tue 06 Jul 1999 - 14:33:03 IDT
> Will support to set the mtrr (to enable write-combining for the region)
> for the video card automatically be added to svgalib?
That won't be hard, I'll probably do it sometime, if no one else will
meanwhile.
This has two parts: setting mtrrs for the linear memory region (all cpus),
and setting mtrrs for the a0000-affff region. The first is available with
the current kernel mtrr support, but the second, which is more important
for svgalib applications needs a patch to the mtrr code. I wrote such a
patch, but Richard Gooch has not yet merged it into his official mtrr
patch.
If any one wants the patch for testing (intel only), please tell me.
There are two demos to test the speed of writing to memory: speedtest (for
a0000 region), and linearspeed (for linear region). The results on my
computer (Celeron 300A, RagePro 8MB SDRAM), MB/s:
speedtest linearspeed
without mtrrs 29 29
with mtrrs 91 240
--
Matan Ziv-Av matan@svgalib.org
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