SSRAM to DDR buffer copy

Hello,

i've tried to copy a buffer stored in the SSRAM (2 Mbytes) that is filled by a VHDL block to a file, on DDR.

Here is my code :

void dumpDataToFile(void){
    unsigned int addr, dataLength;
    unsigned char *buffer;
    FILE * outfile;
    dataLength= 2*1024*1024;
    buffer=(unsigned char *)malloc(dataLength);
     addr=(unsigned int *)SRAM_BASE;
 
    memcpy(buffer, addr, dataLength);
 
    outfile = fopen("data.bin", "wb" );
    fwrite (buffer, dataLength, 1, outfile);
    fclose (outfile);
    free(bufferimg);
}

It works, but it's dramatically slow.

About 4MBytes/sec.

the file is in ramdisk, DDR as i said, so i don't understand why this is so slow.

For my project, i don't need 200MB/s, but at least 15~20MB/s.

both SSRAM and DDR have huge transfer rate compare to that poor 4MB/s

i've tested each code line and it seems that for now it is the memcpy that slow down the function.

read only in sram => fast

fwrite => fast

i've tested to read myself too, insteed of using memcpy and result are quite the same...

My development platform is the cyclone II dev board, with a nios II and uClinux with 2.6.30 kernel.

Any ideas on how i can increase my transfert rate ?

Thank you in advance