Intel SNA vs. UXA On Ivy Bridge (July 2012)

[whaevr]

How do I figure out how what acceleration method is currently being used? Is there some kind of command I can issue? I just want to be able to make sure I have my xorg options set correctly

[dcc24]

How do I figure out how what acceleration method is currently being used? Is there some kind of command I can issue? I just want to be able to make sure I have my xorg options set correctly

If you didn't explicitly enable SNA (see one of the previous posts), you are using UXA.

[GreatEmerald]

Looking at /var/log/Xorg.0.log might give some clues about that, too.

[bwat47]

Latest intel driver in arch linux has sna support (if you do the xorg.conf change), so I enabled it on my ironlake machine to test. Can't say I've noticed much difference in real world usage yet, but it didn't break anything either so I guess there's that

Does anyone know what kind of "real world" usage would show sna's improvements?

[bwat47]

Looking at /var/log/Xorg.0.log might give some clues about that, too.

Correct, I just checked mine and it does seem to tell you if its initialized:

[ 12.881] (II) intel(0): SNA initialized with Ironlake backend

[ickle]

Latest intel driver in arch linux has sna support (if you do the xorg.conf change), so I enabled it on my ironlake machine to test. Can't say I've noticed much difference in real world usage yet, but it didn't break anything either so I guess there's that

Does anyone know what kind of "real world" usage would show sna's improvements?

Well, I've obviously completedly failed if you haven't noticed any of your common tasks improved by SNA. So what is your common workload?

[Kano]

Well SNA enabled triggers more often the xserver crash with debian wheezy when kde 4 effects are turned off/on. As i still need that to get teerfree video i would like to know what patches are needed for the xserver - best force em to be added to the debian wheezy xserver...

[bwat47]

Well, I've obviously completedly failed if you haven't noticed any of your common tasks improved by SNA. So what is your common workload?

Maybe I'm just bad at noticing these things

Generally on this laptop I don't do anything too heavy, web browsing, videos, music, text editing.

[bwat47]

Ok, I definitely notice firefox seems a lot snappier with sna enabled

[Gusar]

So for the first time after a long while, I used my Ironlake machine full-time today. And I had this weird feeling all the time as if the display is out of focus. In trying to figure it out, I switched from SNA back to UXA. And what do you know, the feeling was gone immediately. So I took some screenshots.

Here a toolbar button with UXA:

The same toolbar button with SNA:


Note in particular the right edge. You might think that the difference is very small, but it's enough to give me the weird feeling.

Versions of relevant packages are xf86-video-intel-2.20.3, cairo-1.12.2, gtk2-2.24.11, the theme being rendered is Clearlooks. Such a tiny thing, but you know what, I'll stick with UXA for the time being. I'm very sensitive to such things. For example, I use the lcdlegacy freetype filter for fonts, because what the lcddefault filter renders is way too blurry for my eyes.