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some optimization for the main.cc code #3

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some optimization for the main.cc code #3

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a924e74
Update main.cu
asimay Aug 11, 2023
9fc2507
Update main.cu
asimay Aug 11, 2023
05628c4
Update main.cu
asimay Aug 14, 2023
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10 changes: 5 additions & 5 deletions 06_MemoryBasics/src/main.cu
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@asimay asimay Aug 14, 2023

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sorry, maybe the line 76: cudaMemcpyToSymbol(&cFoo, &bar, sizeof(int)); modification is wrong.
please ignore this line.

Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@


// Declaration of a device variable in constant memory
__constant__ int cFoo;
__device__ __constant__ int cFoo;

__global__ void ReadConstantMemory()
{
Expand All @@ -23,14 +23,14 @@ __global__ void WriteGlobalMemory(int* __restrict dOutPtr)
*dOutPtr = dFoo * dFoo;
}

__device__ void WriteAndPrintSharedMemory(int* sFoo)
__device__ void WriteAndPrintSharedMemory(int* __restrict sFoo)
{
// Write a computed result to shared memory for other threads to see
sFoo[threadIdx.x] = 42 * (threadIdx.x + 1);
// We make sure that no thread prints while the other still writes (parallelism!)
__syncwarp();
// Print own computed result and result by neighbor
printf("ThreadID: %d, sFoo[0]: %d, sFoo[1]: %d\n", threadIdx.x, sFoo[0], sFoo[1]);
printf("ThreadID: %d, sFoo[%d]: %d \n", threadIdx.x, threadIdx.x, sFoo[threadIdx.x]);
}

__global__ void WriteAndPrintSharedMemoryFixed()
Expand Down Expand Up @@ -73,7 +73,7 @@ int main()
GPU memory. Can be updated with cudaMemcpyToSymbol.
This syntax is unusual, but this is how it should be
*/
cudaMemcpyToSymbol(cFoo, &bar, sizeof(int));
cudaMemcpyToSymbol(&cFoo, &bar, sizeof(int));
ReadConstantMemory<<<1, 1>>>();
cudaDeviceSynchronize();

Expand Down Expand Up @@ -140,4 +140,4 @@ a syncwarp, so that other threads may fail to see it. You might need a block
size larger than 32 threads for this to happen and you may have to let the writing
thread do some "fake" work to delay its write to shared memory. Or it may work
immediately :) A solution should be provided by the following code sample.
*/
*/