On Wed, Mar 26, 2003 at 09:14:37AM -0800, Ian Romanick wrote:
> Philip Brown wrote:
> > Consider the GLX_dri_reserve_mem as equivalent to sbrk()
> > Then have a more local memory allocator for subdividing the large chunk.
> > That's going to be a lot more efficient that relying on the XFree routines
> > to do fine-level memory management anyways. xfree's routines arent really
> > optimized for that sort of thing, I think.
>
> Okay. You're just not listening. THAT WON'T ALLOW US TO IMPLEMENT A
> FUNCTIONING 3D DRIVER. Textures memory is like a cache that is shared
> by multiple running processes. We need to be able to do the equivalent
> of paging out blocks from that cache when one process needs more memory.
> An OS needs something under sbrk in order to implement paged memory,
> and so do we.
eh?
Card has 32 megs of VideoRAM.
Initialization phase:
X grabs 4 megs for actual video display
X grabs 1 meg(?) for pixmaps
DRI/GLX starts, notices that there is 27 megs free.
Decides to be nice, and only pre-alloc 16 megs.
Parcels out that 16 megs to clients somehow.
(clients will probably grab memory in 2-4meg chunks from GLX,
then use "local" memory manager on that)
....
New client comes in. Requests new corse chunk o' VRAM from GLX
Oops. we've used up the 16 megs pre-allocated.
Used to be 11 megs free, but X server has been busy, and there is
now "only" 8 megs free.
GLX calls xf86AllocateOffscreenLinear() to grab another 4 megs of
VRAM from the X server, then hands some part of it off to the new
client
> ... Instead, it will make a lot of work for DRI developers (every process
> with a GL context will have to be notified when any context makes a
> magic sbrk call).
No, you dont have to notify all GL clients. See above.
Ya know, I heard this guy "Keith Whitwell" wrote some nice mmXXX()
routines in 1999 that, coincidentally enough, handle *exactly* *this* *type*
*of* *situation* for a "local memory manager" for GLX clients.
Now, what are the odds of that? Maybe we could get that guy to help out
here somehow...
:-) :-) :-)
-------------------------------------------------------
This SF.net email is sponsored by:
The Definitive IT and Networking Event. Be There!
NetWorld+Interop Las Vegas 2003 -- Register today!
http://ads.sourceforge.net/cgi-bin/redirect.pl?keyn0001en
_______________________________________________
Dri-devel mailing list
[EMAIL PROTECTED]
https://lists.sourceforge.net/lists/listinfo/dri-devel
