kupl_memcpy

Interface Definition

int kupl_memcpy(void *dst, const void *src, size_t count);

• Currently, the maximum copy length supported by kupl_memcpy is UINT32_MAX. That is, the value of count cannot exceed UINT32_MAX.
• The value of count must be less than the actual size of the memory to which src and dst point.

Environment Variables

KUPL uses KUPL_MEMCPY_MT_THRESHOLD and KUPL_SDMA_MEMCPY_THRESHOLD to determine the packet size thresholds for the multi-thread memcpy capability and the SDMA memcpy capability, respectively. By default, the multi-thread memcpy threshold is 512 KB, and the SDMA memcpy threshold is 2 MB.

kupl_memcpy supports three methods: single-thread glibc memcpy, SDMA memcpy, and multi-thread memcpy. If SDMA is enabled in the environment, determine a memcpy method based on KUPL_SDMA_MEMCPY_THRESHOLD. Data packets smaller than this threshold use glibc memcpy; otherwise, SDMA memcpy is utilized. Similarly, if SDMA is disabled, use KUPL_MEMCPY_MT_THRESHOLD to determine a memcpy method. Data packets smaller than this threshold use glibc memcpy; otherwise, multi-thread memcpy is utilized.

You can define the thresholds for multi-thread memcpy and SDMA memcpy by configuring KUPL_MEMCPY_MT_THRESHOLD and KUPL_SDMA_MEMCPY_THRESHOLD. These configurations are also used by the kupl_memcpy2d interface to determine the optimal memcpy method.

Parameters

Return Value

• Success: KUPL_OK
• Failure: KUPL_ERROR

Examples

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#include <stdio.h> 
#include <stdlib.h>
#include <assert.h>
#include "kupl.h" 

int main() 
{ 
    int len = 1024; 
    char *src = (char *)kupl_malloc(KUPL_MEM_DEFAULT, len);
    char *dest = (char *)kupl_malloc(KUPL_MEM_DEFAULT, len);
    if (src == nullptr || dest == nullptr) {
        goto error;
    }
    for (int i = 0; i < len / sizeof(char); i++) {
        src[i] = i ;
        dest[i] = 0;
    }
    int ret = kupl_memcpy(dest, src, len);
    assert(ret == KUPL_OK);
error:
    kupl_free(KUPL_MEM_DEFAULT, src);
    kupl_free(KUPL_MEM_DEFAULT, dest); 
    return 0; 
}

• The preceding example demonstrates the memory copy process.
• The kupl_memcpy function copies the content in the src array to the dest array. len represents the size of the copied memory.