From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grigori Goronzy Subject: Re: [PATCH 4/5] r600g, radeonsi: Use write-combined persistent GTT mappings Date: Thu, 17 Jul 2014 12:56:58 +0200 Message-ID: <53C7ABFA.6090804@chown.ath.cx> References: <1405591275-14461-1-git-send-email-michel@daenzer.net> <1405591275-14461-10-git-send-email-michel@daenzer.net> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0474667306==" Return-path: In-Reply-To: <1405591275-14461-10-git-send-email-michel@daenzer.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: =?UTF-8?B?TWljaGVsIETDpG56ZXI=?= , dri-devel@lists.freedesktop.org, mesa-dev@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --===============0474667306== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="PORlxI0aAQaOKbxCDtoA4UVwQ0vx58VCd" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --PORlxI0aAQaOKbxCDtoA4UVwQ0vx58VCd Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 17.07.2014 12:01, Michel D=C3=A4nzer wrote: > From: Michel D=C3=A4nzer >=20 > This is hopefully safe: The kernel makes sure writes to these mappings > finish before the GPU might start reading from them, and the GPU caches= > are invalidated at the start of a command stream. > Aren't CPU reads from write-combined GTT memory extraordinarily slow, because they're uncached? And don't you need the right access patterns to make write combining perform well? Grigori > Signed-off-by: Michel D=C3=A4nzer > --- > src/gallium/drivers/radeon/r600_buffer_common.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) >=20 > diff --git a/src/gallium/drivers/radeon/r600_buffer_common.c b/src/gall= ium/drivers/radeon/r600_buffer_common.c > index 40917f0..c8a0723 100644 > --- a/src/gallium/drivers/radeon/r600_buffer_common.c > +++ b/src/gallium/drivers/radeon/r600_buffer_common.c > @@ -131,7 +131,7 @@ bool r600_init_resource(struct r600_common_screen *= rscreen, > res->b.b.flags & (PIPE_RESOURCE_FLAG_MAP_PERSISTENT | > PIPE_RESOURCE_FLAG_MAP_COHERENT)) { > res->domains =3D RADEON_DOMAIN_GTT; > - flags =3D 0; > + flags =3D RADEON_FLAG_GTT_WC; > } > =20 > /* Tiled textures are unmappable. Always put them in VRAM. */ >=20 --PORlxI0aAQaOKbxCDtoA4UVwQ0vx58VCd Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlPHrI8ACgkQB4i2VYtEHqn23gCgl1tIGamqIgDYR6Xhtnye+/iA YMkAnA50e0C8vriJNgIQdms52XGDueCo =+B70 -----END PGP SIGNATURE----- --PORlxI0aAQaOKbxCDtoA4UVwQ0vx58VCd-- --===============0474667306== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel --===============0474667306==--