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<p class="MsoNormal">Hello Nova team,<o:p></o:p></p>
<p class="MsoNormal"> During the Cyborg discussion at Rocky PTG, we proposed a flow for FPGAs wherein the request spec asks for a device type as a resource class, and optionally a function (such as encryption) in the extra specs. This does not seem to work
well for the usage model that I’ll describe below.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">An FPGA device may implement more than one function. For example, it may implement both compression and encryption. Say a cluster has 10 devices of device type X, and each of them is programmed to offer 2 instances of function A and 4 instances
of function B. More specifically, the device may implement 6 PCI functions, with 2 of them tied to function A, and the other 4 tied to function B. So, we could have 6 separate instances accessing functions on the same device.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In the current flow, the device type X is modeled as a resource class, so Placement will count how many of them are in use. A flavor for ‘RC device-type-X + function A’ will consume one instance of the RC device-type-X. But this is not
right because this precludes other functions on the same device instance from getting used.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">One way to solve this is to declare functions A and B as resource classes themselves and have the flavor request the function RC. Placement will then correctly count the function instances. However, there is still a problem: if the requested
function A is not available, Placement will return an empty list of RPs, but we need some way to reprogram some device to create an instance of function A.
<o:p></o:p></p>
<p class="MsoNormal">
<o:p></o:p></p>
<p class="MsoNormal">Regards,<o:p></o:p></p>
<p class="MsoNormal">Sundar<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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