On Thu, 5 Sep 2002, Michel Lanners wrote:
> On 4 Sep, this message from Mark Vojkovich echoed through cyberspace:
> >> Is there any way to grab a screenshot really fast. I mean like a 1280x1024
> >> 32bbp screenshot in a couple of milliseconds? I am using XShmGetImage()
> >> right now, but a screenshot of the size mentioned above takes about 110 to
> >> 120 milliseconds. Doing the math this gives me a bandwidth of about 40 to
> >> 45 MB/s. Surely there must be a faster way of doing it.
> >>
> >> The system i am sitting on is a Linux box, XFree 4.2.0, nVidia graphics
> >> (GF2) with the nVidia binary driver.
> >>
> > No, there's not a way to copy quickly from the framebuffer.
> > Reads across AGP are limited to PCI bandwidth. I am seeing over
> > 100 MB/sec in general though (closer to 150 MB/sec on fast P4s).
>
> Would there be a way to use the graphic chip's blitter to copy the
> framebuffer contents over AGP to main memory?
>
> Cheers
The nvidia driver does use the graphics engine to do the copy.
Running that benchmark on other drivers you'll see they get about
a tenth the performance of the nvidia driver.
mark.
_______________________________________________
Xpert mailing list
[EMAIL PROTECTED]
http://XFree86.Org/mailman/listinfo/xpert
