"What" is the Unified Memory?

Dear all

I really wonder “what” is the Unified Memory. I mean In HW, there are GPU’s memory like shared memory, L1, L2 Memory etc.

and CPU memory. There are no “Unifed Memory” in real parts. In NVIDIA’s document, they said [with single pointer, we can

access memory from CPU or GPU].

In first. I thought using Unified Memory means GPU and CPU using host memory with single pointer. But I think that is wrong.

So, my question is this. If we use Unified Memory, what parts really used that time?

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usually this feature called “virtual memory”. it means that address space for both memories are common, and CPU/GPU hardware ensures that memory page will be copied to the device trying to use it. so you don’t need to worry - just alloc memory and use it, and hardware+driver will take the rest

[url]Programming Guide :: CUDA Toolkit Documentation

Hi,

Are there any benchmarks, or comparative tests, that indicate the latency incurred by using main memory?
Of course, I assume that Unified Memory is optimised to:
give a higher priority to GPU memory in the combined memory space; and
the job of marshalling data between memory-spaces.