Virtual GEM Is Coming For Linux 4.1

[phoronix]

Phoronix: Virtual GEM Is Coming For Linux 4.1

There's already been a fair amount of code building up for the DRM graphics subsystem for the Linux 4.1 kernel and a new feature was just committed to Git last night...

http://www.phoronix.com/scan.php?page=news_item&px=vGEM-Linux-4.1-Feature

[curaga]

Michael, benchmarks of llvmpipe with vs without?

[Kemosabe]

Is there any practical use for software renderers? To debug graphics drivers or sth like that? And why do 3 of them come with mesa?

[nanonyme]

Is there any practical use for software renderers? To debug graphics drivers or sth like that? And why do 3 of them come with mesa?

Answer to third would be legacy reasons, I'd say

[curaga]

Is there any practical use for software renderers? To debug graphics drivers or sth like that? And why do 3 of them come with mesa?

To debug GL software, or to do (often non-interactive) rendering on a computer with no GPU, or to give you Gnome 3 bling without a GPU/with only an old GPU.

swrast: legacy reasons
softpipe: does not need the monster that is llvm -> easier to bootstrap new platform ports, etc
llvmpipe: for actual use

[smitty3268]

swrast: legacy reasons
softpipe: does not need the monster that is llvm -> easier to bootstrap new platform ports, etc
llvmpipe: for actual use

To add to that:

swrast is generally only used these days to provide helper functions to old hardware drivers, such as i915. No real development is done on it.

llvmpipe is generally what users use, if they are choosing to use a software renderer. High performance (for a software renderer) is a goal.

softpipe is built on a similar gallium framework to llvmpipe, but is vastly simpler to debug and prototype new features in. It also doesn't have the requirement of porting llvm to new platforms, making it more portable. Performance generally isn't worried about, so things can be done the slow but technically more correct way while sometimes llvmpipe will stick in faster approximations that work *good enough*.