Re: MTRR's: What kind of speedup? Any regions besides framebuffer?

Richard Gooch (rgooch@atnf.CSIRO.AU)
Tue, 27 Jan 1998 20:38:18 +1100

Benjamin Redelings, I writes:
> Hi, I have a PPro 150->166 with bus speed 66MHz. I notice on loading
> proform.o (with kernel 2.1.82) that I get an improvement of 17.2->20.7
> fps at 512x384 in q2test (Quake II Test). I guess thats a 20% increase
> but it doesn't seem THAT big...is that normal? High? Low?
> I'm also wondering if there are other regions besides the framebuffer
> than can/should be set to Write-Combining. I'm using XFree86 3.3.1 with
> a Matrox Mystique w/ 2Mb SGRAM. (Also, anyone think I could get an
> improvement by using the XSuse server?)
> I'm interested in this mainly as a benchmark...but perhaps my CPU isn't
> stressing the bus out cuz it isn't fast enough ;)

I don't know what your test does, but image write operations should be
2.5 to 2.8 times faster. BTW: have you seen MTRR v1.5? It's at:
http://www.atnf.csiro.au/~rgooch/kernel-patches.html

It gives a nice /proc/mtrr interface.

Regards,

Richard....