The AMD Radeon Performance Is Incredible On Linux 3.12

[asdfblah]

Somehow I get the impression that cheap gpus run well and expensive ones run bad.

I tried to use the open source driver for my hybrid HD 7970M.

Auto poweroff ("runtime pm") does not seem to be in 3.12 yet. It's pretty important because with vgaswitcheroo if you power off the radeon gpu in X and then go to a tty and then back to X, the driver locks up.

With DPM enabled:
When starting X on boot it locked up with a cursor in the upper left corner. Starting X a little while after boot worked.
When powering off the radeon GPU with vgaswitcheroo X locks up completely.

That's not even performance or features, that's the most basic stuff like not locking up X.

is this it? https://bugs.freedesktop.org/show_bug.cgi?id=70391 if so, add yourself to the bug report, please

[Michael]

Wild guess. Could it be the change not related to GPU driver at all? I just remembered the discussion related to ondemand vs performance governor. It was shown by Vadim that ondemand could drop the frame rates. So is it possible that this problem was fixed in 3.12?

I haven't seen any GPU Haswell performance changes out of 3.12 vs. 3.11.

[agd5f]

On a somewhat unrelated note, Michael's 6570 seem to be performing properly relative to the other asics on both 3.11 and 3.12.

[agd5f]

Wild guess. Could it be the change not related to GPU driver at all? I just remembered the discussion related to ondemand vs performance governor. It was shown by Vadim that ondemand could drop the frame rates. So is it possible that this problem was fixed in 3.12?

Possibly. It could be that the cards were previously CPU limited, and due to some change in 3.12, they are no longer CPU limited. That would explain the larger boost on higher end cards since the lower end cards would already be nearer to being GPU limited.

[Rakot]

I haven't seen any GPU Haswell performance changes out of 3.12 vs. 3.11.

According to this article http://www.gearsongallium.com/?p=760 r600g was affected by this problem. Probably intel's drivers are not CPU sensitive. At least I didn't see anything like this in any intel test.

[Rakot]

Possibly. It could be that the cards were previously CPU limited, and due to some change in 3.12, they are no longer CPU limited. That would explain the larger boost on higher end cards since the lower end cards would already be nearer to being GPU limited.

So in this case the test 3.11+performance governor vs 3.12 at stock configuration will prove this guess.

Michael, can you run just one more test on one of the affected card with 3.11 + performance governor in one of the game which showed dramatic speedup? If the result will be the same as in the case of 3.12 you can safely conclude that this is the reason.

[Luke]

CPU governor setting still effects framerate the same way here

Possibly. It could be that the cards were previously CPU limited, and due to some change in 3.12, they are no longer CPU limited. That would explain the larger boost on higher end cards since the lower end cards would already be nearer to being GPU limited.

On my Radeon HD6750, one game, Critter/Criticalmass (a 2d galaxians clone) is strongly affected by the CPU governor setting ("ondemand" slows it down). Even on 3.12, that can be the difference between 300 and 600+fps on this very light 2d game, one wich no doubt lets the CPU slow down easily. On Scorched3d my results are always all over the place due to different maps, but not sure if there is any effect. In 0ad, no effect as the game is CPU limited and holds the CPU to maximum frequency at all times.

[asdfblah]

let's say the cpu governor is a factor for r600... what about fglrx? how does one compares to the other? what if you run BOTH with the "performance" setting?

[grigi]

I found the CPU Governor definitely affects the smoothness of my laptop with Fglrx. It doesn't really seem to affect benchmarks, but definitely improves gameplay and general desktop responsiveness.

Also the default governor settings from 3.10 onwards seems to have largely improved things for me.

[liam]

Somehow I get the impression that cheap gpus run well and expensive ones run bad.

I tried to use the open source driver for my hybrid HD 7970M.

Auto poweroff ("runtime pm") does not seem to be in 3.12 yet. It's pretty important because with vgaswitcheroo if you power off the radeon gpu in X and then go to a tty and then back to X, the driver locks up.

With DPM enabled:
When starting X on boot it locked up with a cursor in the upper left corner. Starting X a little while after boot worked.
When powering off the radeon GPU with vgaswitcheroo X locks up completely.

That's not even performance or features, that's the most basic stuff like not locking up X.

You are aware that the SI boards are a serious wip (completely new driver vs r600). If you go back to the high end 6xxx you'll see vastly better performance.