Can Cuda use shared memory?

Shared memory is a powerful feature for writing well optimized CUDA code. Access to shared memory is much faster than global memory access because it is located on chip.

How do I declare a shared memory?

Declaring Shared Memory Shared memory is declared in the kernel using the __shared__ variable type qualifier. In this example, we declare an array in shared memory of size thread block since 1) shared memory is per-block memory, and 2) each thread only accesses an array element once.

Can two processes share memory?

Yes, two processes can both attach to a shared memory segment. A shared memory segment wouldn’t be much use if that were not true, as that is the basic idea behind a shared memory segment – that’s why it’s one of several forms of IPC (inter-Process communication).

What is shared system memory?

Shared memory represents system memory that can be used by the GPU. Shared memory can be used by the CPU when needed or as “video memory” for the GPU when needed. The sum of the memory used by all processes may be higher than the overall GPU memory because graphics memory can be shared across processes.

Is shared GPU memory the same as VRAM?

Shared system memory means sharing of the system memory with the onboard graphics chip. Dedicated vram means applications using memory for rendering purposes will use only the memory on the discrete graphics card thus drastically improving performance.

How do threads copy data from global memory to shared memory?

Threads copy the data from global memory to shared memory with the statement s [t] = d [t], and the reversal is done two lines later with the statement d [t] = s [tr].

Are misaligned data accesses a problem with CUDA hardware?

For recent versions of CUDA hardware, misaligned data accesses are not a big issue. However, striding through global memory is problematic regardless of the generation of the CUDA hardware, and would seem to be unavoidable in many cases, such as when accessing elements in a multidimensional array along the second and higher dimensions.

How to declare a shared memory array size at compile time?

If the shared memory array size is known at compile time, as in the staticReverse kernel, then we can explicitly declare an array of that size, as we do with the array s. In this kernel, t and tr are the two indices representing the original and reverse order, respectively.

Can a shared memory request for a warp be split?

A shared memory request for a warp is not split as with devices of compute capability 1.x, meaning that bank conflicts can occur between threads in the first half of a warp and threads in the second half of the same warp.