Carmack On 3D Linux

Gaza wrote in to send us an Essay written by John Carmack to help in making GL drivers for Linux. Its kinda techie stuff, but its still interesting.

Comments

To bring up another point

[Anonymous Coward]

I think Carmack makes an excellent point about X's rendering pipeline. Under the X Window System, the Xclients (any X program) update the display by writing data to the X Display Server via a socket.

While this is great for doing things over a network, it limits performance, especially performance where huge chunks of data must be thrown around (like in higher resolutions/depth) on the local machine.

UNIX (LOCAL) sockets speed this up by about 100% (or more or less, depending on the implementation), but it's still fundamentally flawed.

Each write to the X Server must involve the kernel's interaction. This introduces more overhead than it probably ever should. Especially if you want excessively high performance.

It's a simple fact. While the X Server remains a seperate process that can only be updated via a local socket, performance will be gated.

I'm not an expert on The X Window System, so I really don't know what a viable solution would entail. I'm just throwing this out: What if we were to make an extension to Xlib that would ask the X Server if it would allow the Xclient to mmap part of the framebuffer (it's client area) or just mmap the entire thing? All subsequent Xlib calls would write to the framebuffer.

This introduces a whole mess of issues, but we need to do SOMETHING. Anyone want to open up discussion? or tell me how wrong I am? :)

--Michael Bacarella