Pushing image transport logic down the stack

[Alan Cox]

Ar Sul, 2006-09-03 am 19:15 -0400, ysgrifennodd Owen Taylor:
> I didn't specify whether the second copy above was being done by
> the CPU or the video card ...

If you are doing format conversion then the first copy is as good as
free on a PC class system. If you are not then it is a client memory
management issue.

> I don't think the SHM extension really works out very well for
> most applications once you take a broader view of success.

Any "direct" API I can imagine is going to look something like

Allocate Object
Put Data In It
Pass To X Server

Once you want to do reuse then you either have the server telling the
client when it has finished and/or refcounting.

I'm not sure how much more we could do to improve on the state of
things, and Sys5 shared memory (or perhaps posix shared memory would be
nicer these days) has the same life model that is needed as well as
being pageable.

What sort of an API are you thinking of here ?

Alan