From Tungsten Graphics
TTM Memory Manager
Tungsten Graphics created the TTM memory manager, an advanced video memory manager.
Compared to the previous DRI memory managers, TTM implements:
- Dynamic tracking of buffers referenced by active rendering commands.
- Full access to all addressable video memory for every 3d context.
- A fence facility for hardware synchronization.
- A guarantee that contents of textures and other video memory buffers will be preserved, and therefore require no backing store in main memory.
On IGP hardware like the i915, TTM takes advantage of the hardware translation tables (ie GART tables) to dynamically swap textures and other buffers into the video address space as required for the current rendering task. This provides 3d contexts with very fast texture upload paths and an almost unlimited texture memory pool.
Overview of the TTM memory manager
The TTM memory manager has allowed TG to add support for framebuffer objects and other recent OpenGL extensions to the i915tex Mesa driver.