I'm working my way through some vulkan examples, and I just want to make sure that my understanding of queues is correct.
Each physical device has a set (\(Q\)) of queue families, and each queue family has some amount \(N_{q \in Q}\) queues that can be used. When creating a logical device, you specify some amount of logical queues you want to create, such that the sum of each queueCount property for each queue family \(q\) is not greater than \(N_q\) (maybe some unforseen circumstance has led us to a VkDeviceQueueCreateInfo array of [(family=0,cnt=2), (family=1,cnt=1), (family=0,cnt=1)]). The driver will take care of multiplexing the queues, e.g. if I create two logical devices with 8 queues each from the same queue family, whether or not the driver assigns both logical queues \(0, \dots, 7\) to physical queues \(0, \dots 7\) or \(0, \dots, 15\) is none of my concern, the plumbing is all taken care of by the driver.
Different queues can be submitted in paralle, but extra safety should be taken care of to make sure that the command buffers don't screw with each other if they interact with the same object. Retrieving queues gets retrieved in the order created. e.g. If my VkDeviceQueueCreateInfo array looked like [(cnt=2,priorities=[1.0,0.5]), (cnt=1,priorities=[0.2])], I can expect that vkGetDeviceQueue(device, family, [0, 1, 2]) has priorities [1.0, 0.5, 0.2]). Queue priorities are a relative number, such that the following metaphor makes sense: if each queue can be represented as a thread, a priority of 1.0 means that the thread should work as hard as it possibly can while a priority of 0.5 means that it should only work half as hard, with the union of all threads representing the queue processing power of the entire physical device.
If I said something wrong, please feel free to correct me. I want to make sure I'm not misunderstanding something fundamental.
