Could the global variable shared between two kernels in the same aocx file?

Correct, I mean the file scope global variables. Do they stay in DDR? I want to share a lot of intermediate results between two kernels, which are executed sequentially. So, the shared data will be safe. But I do not want to share the the intermediate results via CPU. Another question: if the two kernels access simultaneously, do you plan to use atomic operations to share data?

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If by global you mean file scope variables the answer is yes but there would be no syncronization between the kernels accessing that shared data. If the kernels operate sequentially then there would be no properly but if they operate concurrently then you run the risk of a data hazard.

I could write more but if you described what you are trying to achieve I can probably describe a safer method to share data amungst kernels.

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