[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window
From: |
Jamie Lokier |
Subject: |
Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window |
Date: |
Mon, 8 Sep 2008 14:21:57 +0100 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
Stefano Stabellini wrote:
> > A good quality guest _expects_ that reading its video RAM will be
> > slow, and only writes to its video RAM, and possible by preparing images
> > off-screen then wide block transfers. :-)
>
> That is a really good point.
> Usually the safe way to handle the video ram VS main memory problem is
> to write to main memory then copy the whole buffer to video ram every so
> often.
> But in our case the guest thinks that he is writing to video ram
> already, so in theory he is already using all precautions needed to
> handle the latency problem.
> It is actually probable that the guest is handling another buffer in his
> own memory and syncing that one with what he thinks to be the video ram.
Yes, especially with any guest in the last 15 years :-), so I would
imagine that mapping to video RAM as directly as you can would give
the best results (e.g. using an OpenGL memory-mapped texture or X11
MIT-SHM image if they're possible to protect safely). That's also
saving power, by the way, even if your machine is plenty fast enough
that extra full-screen image copies aren't humanly visible.
That said, numbers talk better than hand-waving.
-- Jamie
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, (continued)
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Samuel Thibault, 2008/09/07
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Paul Brook, 2008/09/07
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Samuel Thibault, 2008/09/07
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Paul Brook, 2008/09/07
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Samuel Thibault, 2008/09/07
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Paul Brook, 2008/09/07
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Anthony Liguori, 2008/09/07
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Samuel Thibault, 2008/09/07
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Jamie Lokier, 2008/09/07
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Stefano Stabellini, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window,
Jamie Lokier <=
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Stefano Stabellini, 2008/09/05
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Daniel P. Berrange, 2008/09/05
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Stefano Stabellini, 2008/09/05
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Anthony Liguori, 2008/09/06
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Stefano Stabellini, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Jamie Lokier, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Stefano Stabellini, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Jamie Lokier, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Daniel P. Berrange, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Gerd Hoffmann, 2008/09/08