DRI2 vs. DRI3 Radeon Linux OpenGL Performance

[aceman]

Trying to enable DRI3 i get this:
[ 25369.650] (WW) RADEON(0): Option "DRI3" is not used

man radeon do not show any DRI3 option... i'm using xf86-video-ati-7.5.0, mesa-11.0.4 (with --enable-dri3), libdrm-2.4.65 and xorg-server-1.17.3

So how did you try to enable the option? It seems the X server didn't pick up your setting. For me on Slackware it seems to work.

[drSeehas]

... I think only one of these GPUs would need to be tested for that. We got the gist, I don't think all 3 need to be compared.

So you think Northern Islands, Southern Islands and Sea Islands all behave the same?

[higuita]

Trying to enable DRI3 i get this:
[ 25369.650] (WW) RADEON(0): Option "DRI3" is not used

man radeon do not show any DRI3 option... i'm using xf86-video-ati-7.5.0, mesa-11.0.4 (with --enable-dri3), libdrm-2.4.65 and xorg-server-1.17.3

also, kernel 4.2.5 on a slackware64

Any tip why it is failing and how to fix this

[roboman2444]

Thus the difference will only appear when we render faster than the screen can show, meaning no user side improvement.

Thats an improvement for some, as Xonotic, darkplaces, and many open source games only take input once per frame. Its why i disable vsync when using any of these games, because 400 input ticks per second is noticably better than 60. While 500->400 is not as big of a difference as 400->60, it may help.

[AnAkIn]

Then it means arch specifically turns it off by default. Trust me, I tried enabling it but it doesn't work.

Mesa build from lcarlier on the other hand, works as it should.

https://projects.archlinux.org/svntogit/packages.git/tree/trunk/PKGBUILD?h=packages/mesa#n34

It's not turned off in mesa PKGBUILD, and it was working last time I've tried. Will try again later.

[Adriannho]

The option is turned on by default for Linux builds, it doesn't need to be specified.

Then it means arch specifically turns it off by default. Trust me, I tried enabling it but it doesn't work.

Mesa build from lcarlier on the other hand, works as it should.

[AnAkIn]

I think it's a build-time option, so whomever builds mesa has the option either way. And I'm pretty sure the build in the default pacman repo doesn't have it enabled, correct me if I'm wrong.

The option is turned on by default for Linux builds, it doesn't need to be specified.

[kaprikawn]

DRI3 is already enabled by default in mesa.
http://cgit.freedesktop.org/mesa/mes...figure.ac#n762

Since 2014:
http://cgit.freedesktop.org/mesa/mes...39ab3db31fffd9

I think it's a build-time option, so whomever builds mesa has the option either way. And I'm pretty sure the build in the default pacman repo doesn't have it enabled, correct me if I'm wrong.

[kaprikawn]

Great article, I think DRI3 needs publicising more and I think this'll help with that.

I noticed a particular forum post that mentioned this in the last Radeon tests (which I think what Michael was referring to) and I actually enabled it on my Arch gaming machine yesterday from that, though I haven't tested it yet. It was surprisingly difficult to find the instructions on how to enable it. It's one of the few times that the Arch wiki has let me down and I had to reference a few different sources to find the correct instructions, but hey, that's Arch for you.

I echo the sentiment that I wish Arch would enable it by default, or at the very least add a section to the Xorg wiki page that gives instructions. I'll maybe dip my toe in the water of contributing to the wiki by suggesting it.

[AnAkIn]

This bothers me as well. Maybe some arch dev is around and sees this article,
Or someone can link this in their forums.

Anyways, thanks for the article Michael!

DRI3 is already enabled by default in mesa.
http://cgit.freedesktop.org/mesa/mes...figure.ac#n762

Since 2014:

http://cgit.freedesktop.org/mesa/mesa/commit/configure.ac?id=23740ed031f4a5fb308e03a4d239ab3db31fffd9