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Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support
From: |
Jamie Lokier |
Subject: |
Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support |
Date: |
Thu, 31 Jan 2008 09:46:14 +0000 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
Anthony Liguori wrote:
> VGA framebuffer operations come in as memory operations. They're
> tracked by watching what memory gets dirtied. This can only operate at
> a page-granularity so this results in scan-line granularity updates.
> The VNC front-end goes to great lengths to keep a shadowed framebuffer
> and reduce these updates to a smaller update region. You could possibly
> look at refactoring that code. However...
That update region code should probably be moved to something generic
and made into a generic display option.
Reducing update region is logically orthogonal, and could work with
any update method (e.g. local X11, remote X11, local X11-OpenGL,
remote X11-OpenGL, SDL etc.). With some of those, for some people
(especially some but not all remote setups) it might be worth it.
> I would be amazed if screen updates on OS X are so slow that it would
> make a difference if updates are in scanline granularities. The copying
> latency is nothing compared to the other latencies in QEMU. A modern
> processor can move memory at an extremely high speed.
>
> At a refresh rate of 30 times per second, this is only ~4MB of data for
> mouse movements. A typical processor can easily handle many GB of data
> per second.
That's 16MB/frame on an Apple Cinema display at 32bpp, which is
0.5GB/sec. Not too much, but not free either :-)
-- Jamie
- [Qemu-devel] [patch] cocoa.m - Core Graphics support, Mike Kronenberg, 2008/01/21
- Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support, Alexander Graf, 2008/01/30
- Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support, Pierre d'Herbemont, 2008/01/30
- Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support, Anthony Liguori, 2008/01/30
- Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support,
Jamie Lokier <=
- Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support, Julian Seward, 2008/01/31
- Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support, Anthony Liguori, 2008/01/31
- Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support, Jamie Lokier, 2008/01/31
- Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support, Alexander Graf, 2008/01/31
Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support, Mike Kronenberg, 2008/01/30