Re: [Chromium-dev] Display list management

[James S. <arr...@gm...>]

My understanding is that a display list is basically a sequence of
OpenGL commands that are sent to their server and from that point
onward may be invoked by a single command. In this way, we avoid
having to send the whole sequence to the server every time we use it
(it saves bandwidth).

The replicate has something to do with the VNC SPU, which I am not
familiar with yet.

The tilesort SPU performs a number of "optimizations" using display
lists. For example, I think it can compute which tiles the DL (Display
List) effects and send it to only the Render SPUs that are on that
tile (in theory, with the right configuration).
For example the option "auto_dlist_bbox" tells the tilesort SPU to
compute a bounding box for the dlist and only send CallList commands
to tiles that will be effected by that dlist.
The "lazy_send_dlists" sends DLs only to the tiles that need them, and
only when they need them. ig. if a DL is only needed on one tile, it
is only sent to that tile. If it later is needed on another tile it is
then sent to the second tile. It optimizes performance.

In general, the Expando SPU would hurt performance, but there is a lot
of things to account for (in a few rare cases it might make things
faster?). My guess is that it is for debugging.

Thank you for your time,
James Steven Supancic III