Date: Wed, 22 Apr 2009 19:55:13 -0500 From: Robert Noland <rnoland@FreeBSD.org> To: Norbert Papke <npapke@acm.org> Cc: freebsd-stable@freebsd.org Subject: Re: dri + ATI: dramatic performance slowdown Message-ID: <1240448113.2142.11.camel@balrog.2hip.net> In-Reply-To: <200904221739.25097.npapke@acm.org> References: <20090420152620.8f89edd5.lehmann@ans-netz.de> <20090421160454.9f5bf40c.lehmann@ans-netz.de> <1240326709.14628.33.camel@balrog.2hip.net> <200904221739.25097.npapke@acm.org>
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--=-+M7gnI8TVjPIjqU9Vp77 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Wed, 2009-04-22 at 17:39 -0700, Norbert Papke wrote: > 0x0/0x100000000 BIOS write-back set-by-firmware active > 0x100000000/0x40000000 BIOS write-back set-by-firmware active > 0xc0000000/0x40000000 BIOS uncacheable set-by-firmware active MTRR is failing in many cases... It seems that your BIOS is doing what both of my newer machines are doing and setting a global range to write-back. I'm also guessing that 0xc0000000 is your framebuffer. We aren't allowed to overlap either of these ranges with a write combined region according to the specs. We would have to handle splitting/merging regions which we don't currently do. I looked at this just the other day, but it is reasonably complex to make that work right and accommodate all of the merging/splitting of regions. We are allowed to use PAT on either of these types of regions to enable write-combining. The drm code already does this for some allocations that are not mapped to user space. The problem with PAT is that all mappings of a given region need to have the same type and we don't currently have any way to specify that for user space mappings. This is fwiw, the last of Nvidia's feature requests as well. I've started looking at it, but I have a lot of learning to do on the vm system still. robert. --=20 Robert Noland <rnoland@FreeBSD.org> FreeBSD --=-+M7gnI8TVjPIjqU9Vp77 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.11 (FreeBSD) iEYEABECAAYFAknvvHEACgkQM4TrQ4qfROOUDQCgiWB0wXqTaNPoUVp8OXQwVZA/ 5CYAniPwHstb/haqeQWS4ndFf7h3jDoK =BP9r -----END PGP SIGNATURE----- --=-+M7gnI8TVjPIjqU9Vp77--
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