Open Stack

On Jul 19, 2016, at 2:58 PM, Chris Friesen <chris.friesen at windriver.com> wrote:

>> Why would a VM program the slot? Wouldn’t it usually be at the host level?
> 
> Are there no cases where a VM might want to download a proprietary program into an FPGA?

That doesn’t sound right to me, but maybe I’m just not that familiar with FPGA specifics. In general, VMs don’t control their hosts. It would also bring up some complications, such as what should happen when you delete that VM: does the FPGA have to be reset to its original state?

>> I’m still not seeing the need for nesting. If you have a single FPGA with 8 slots, when you program the slots with accelerators, you now have 8 consumable resources. The fact that they came from a particular FPGA unit doesn’t seem relevant from a scheduling perspective.
> 
> If you want to be able to provide an FPGA as either a whole un-programmed FPGA or as pre-programmed resources, you'd presumably need to know which whole FPGAs are available and which have been fractionally allocated, no?

An unprogrammed FPGA is a particular resource class. When you program it, you are removing one of that class and creating one or more of a new resource class (e.g., an encryption accelerator program). There isn’t a need to nest anything.

> I agree that if you are only going to have the host program the FPGA and then make the resources available then the scheduler doesn't need to know about whole FPGAs.

That was where we left the discussion in Austin, so that was my assumption.


-- Ed Leafe