Hardware virtual memory on all Radeon HD 7XXX cards?

[bbot]

I have a question: Is Hardware virtual memory support on all HD 7000 series video cards? I have heard a rumor that only cards with Tahiti (HD 79XX) and HD7790 support hardware virtual memory.

 

[OpenGL guy]

I have a question: Is Hardware virtual memory support on all HD 7000 series video cards? I have heard a rumor that only cards with Tahiti (HD 79XX) and HD7790 support hardware virtual memory.

Yes, it's enabled for all HD 7xxx cards. OpenCL actually uses HW VM on HD 5xxx and 6xxx in Windows as well.

 

[moozoo]

How does this relate to Huma?
And is this impacted by the os being 64bit?
I believe you have to use an unofficial environment variable to enable 64 bit address pointers in amd opencl

 

[OpenGL guy]

And is this impacted by the os being 64bit?

No.

 

[moozoo]

Is the hardware virtual memory support in the HD 7xxxx cards, cache coherent?

 

[Davros]

does this mean 7xxxx cards can now use a swap file ?

 

[OpenGL guy]

Is the hardware virtual memory support in the HD 7xxxx cards, cache coherent?

Cache coherent with what? The CPU? No, the GPU does not share the CPU's page tables.

 

[OpenGL guy]

does this mean 7xxxx cards can now use a swap file ?

No, if the GPU triggered a page fault, there would have to be OS support to handle it, which there isn't.

Virtualization has nothing to do with swap, it just means that the addresses used to access memory are virtual, that is it. The GPU's view of virtual does not match the CPU's.

 

[Davros]

so whats the point of it ?

 

[OpenGL guy]

so whats the point of it ?

Security for one. It's also helpful for OpenCL. I am not going to go into further details.

 

[pMax]

aaah my fault.
There is no support for GPU fault on OS side, i misread the guy above.

 

[Psycho]

I guess it's also helping memory management wrt fragmentation, without moving too much data around.
(also/mostly for normal graphics operation)