memory-access

问题 I am running a memory coalescing experiment on Pascal and getting unexpected nvprof results. I have one kernel that copies 4 GB of floats from one array to another one. nvprof reports confusing numbers for gld_transactions_per_request and gst_transactions_per_request . I ran the experiment on a TITAN Xp and a GeForce GTX 1080 TI. Same results. #include <stdio.h> #include <cstdint> #include <assert.h> #define N 1ULL*1024*1024*1024 #define gpuErrchk(ans) { gpuAssert((ans), __FILE__, __LINE__);

问题 I was wondering if there is any simple way to transform a non-coalesced memory access into a coalesced one. Let's take the example of this array: dW[[w0,w1,w2][w3,w4,w5][w6,w7][w8,w9]] Now, i know that if Thread 0 in block 0 access dW[0] and then Thread 1 in block 0 access dw[1] , that's a coalesced access in the global memory. The problem is that i have two operations. The first one is coalesced as described above. But the second one isn't because Thread 1 in block 0 needs to do an operation

来源： https://stackoverflow.com/questions/63297515/why-opencl-work-group-size-has-huge-performance-impact-on-gpu

问题 I have data laid out in memory in a Structure of Arrays (SoA) or Sturcture of Pointers (SoP) form, and have a way to access that data as though it were laid out in Array of Structure (AoS) form -- code given below. However, I am not too happy about use of struct AoS_4_SoP -- although this struct appears to use templates, it is not really generic since, for example, foo and bar are hard-coded inside it. Two questions/requests: 1) For read-write performance, is AoS access provided as good as

问题 This question already has an answer here : What does the standard say about unaligned memory access? (1 answer) Closed last year . Consider the following code: #include <iostream> int main() { char* c = new char('a'); char ac[4] = {'a', 'b', 'c', 'd'}; unsigned long long int* u = reinterpret_cast<unsigned long long int*>(c); unsigned long long int* uc = reinterpret_cast<unsigned long long int*>(&ac[3]); *u = 42; *uc = 42; std::cout<<*u<<" "<<*uc<<std::endl; } Is this considered as a valid

问题 This question already has an answer here : What does the standard say about unaligned memory access? (1 answer) Closed last year . Consider the following code: #include <iostream> int main() { char* c = new char('a'); char ac[4] = {'a', 'b', 'c', 'd'}; unsigned long long int* u = reinterpret_cast<unsigned long long int*>(c); unsigned long long int* uc = reinterpret_cast<unsigned long long int*>(&ac[3]); *u = 42; *uc = 42; std::cout<<*u<<" "<<*uc<<std::endl; } Is this considered as a valid

问题 I am getting the following type of error. I know it has something to do with me improperly accessing memory, but I don't exactly how. Please help me see where I have gone wrong. *note I have simplified my function and it is not obvious what the variables are doing, I just need to know how I am implementing the function incorrectly or where I am misusing memory access. int my_function(char const *file_name, size_t max) { myStruct.pStore = fopen(file_name,"w+"); //pStore is a FILE* myStruct.max

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 8 days ago . I'm getting Memory permission error before entering main thread. After debugging, the error either in this class here: private: motor LFWheel = motor(PORT10,gearSetting::ratio18_1,false); motor LBWheel = motor(PORT2,gearSetting::ratio18_1,false); motor RFWheel = motor(PORT9,gearSetting::ratio18_1,true); motor

问题 In https://stackoverflow.com/a/57116260/946226 I learned how to verify that a function foo that operates on a buffer (given by a begin and end pointer) really only reads form it, but creating a representative main function that calls it: #include <stddef.h> #define N 100 char test[N]; extern char *foo(char *, char *); int main() { char* beg, *end; beg = &test[0]; end = &test[0] + N; foo(beg, end); } but this does not catch bugs that only appear when the buffer is very short. I tried the

问题 I am writing a simple VM and I have a question on implementing object and structure member access. Since the begin address of a program is arbitrary on each run, and subsequently the address of each and every of its objects is arbitrary too. Thus the only way I can think of to access an object or its member object is by accessing an offset from the "base" pointer, which means there is an arithmetic operation needed to access anything in a program structure. My question is whether this is the