Intel Q35/Q45 fb driver?

Adam Jackson ajax at
Tue Oct 6 11:01:53 PDT 2009

On Tue, 2009-10-06 at 10:26 -0700, McDonald, Michael-p7438c wrote:
> Although this isn't directly related to X11, I'm hoping someone here
> might know if there's a fb driver for the Intel Q35/Q45 chips? We're
> currently using X for our app but the overhead of moving all of the data
> is killing us, performance wise. Essentially, we're doing
>   while (1)
> 	XPutImage();
> as fast as we can. Using RHEL5.3 on a 2.66GHz Q35 box, we get 23
> frames/sec, which is almost acceptable. (A 2.4GHz Dell/nVidia Quadro NVS
> 285 gets 78 frames/sec.) Once we run a hypervisor/separation kernel
> under RH on the Q35, we get a whooping 3 frames/sec! That performance
> isn't acceptable.

Your hypervisor scenario doesn't make a lot of sense to me.  I don't see
what you're trying to accomplish with it.  I guess you're trying to run
the app inside the vm, but displaying to the vm's (emulated) display?
If so, your copy chain (assuming PutImage not ShmPutImage) looks like:

app -> vm kernel -> vm X server -> hv -> host X server -> gpu

Which is pretty dire.  You could just run the app in the vm but display
on the host's X server, which would look like:

app -> host X server -> gpu

which ought to be only marginally slower than your 23fps baremetal.

- ajax
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