PowerQUICC Processorsのトピックlinux aio with mmap https://community.nxp.com/t5/PowerQUICC-Processors/linux-aio-with-mmap/m-p/703276#M2198 <HTML><HEAD></HEAD><BODY><P><STRONG>using mmap64 to get ddr address,then using linux aio to write files,but the speed is very low.if not using mmap , the speed is ok!</STRONG></P><P>int fd_mem;<BR /> unsigned long long ddrStart = 0x200000000ULL;<BR /> unsigned long long ddrPhyAddress = 0x200000000ULL;<BR /> unsigned long long ddrSize = 0x80000000ULL;<BR /> long unsigned int *tmp;<BR /> fd_mem = open("/dev/mem", O_RDWR | O_SYNC);<BR /> if (fd_mem &lt; 0)<BR /> {<BR /> printf("open /dev/mem faild\n");<BR /> return -1;<BR /> }</P><P><BR /> ddrStart = (long unsigned int)mmap((void*)ddrStart, ddrSize,<BR /> PROT_READ | PROT_WRITE,<BR /> MAP_SHARED | MAP_LOCKED | MAP_NORESERVE,<BR /> fd_mem, ddrPhyAddress);<BR /> if ((void *)ddrStart == MAP_FAILED)<BR /> {<BR /> close(fd_mem);<BR /> printf("mmap memory failed\n");<BR /> return -1;<BR /> }</P></BODY></HTML> Thu, 14 Sep 2017 03:44:13 GMT silecy2016 2017-09-14T03:44:13Z linux aio with mmap https://community.nxp.com/t5/PowerQUICC-Processors/linux-aio-with-mmap/m-p/703276#M2198 <HTML><HEAD></HEAD><BODY><P><STRONG>using mmap64 to get ddr address,then using linux aio to write files,but the speed is very low.if not using mmap , the speed is ok!</STRONG></P><P>int fd_mem;<BR /> unsigned long long ddrStart = 0x200000000ULL;<BR /> unsigned long long ddrPhyAddress = 0x200000000ULL;<BR /> unsigned long long ddrSize = 0x80000000ULL;<BR /> long unsigned int *tmp;<BR /> fd_mem = open("/dev/mem", O_RDWR | O_SYNC);<BR /> if (fd_mem &lt; 0)<BR /> {<BR /> printf("open /dev/mem faild\n");<BR /> return -1;<BR /> }</P><P><BR /> ddrStart = (long unsigned int)mmap((void*)ddrStart, ddrSize,<BR /> PROT_READ | PROT_WRITE,<BR /> MAP_SHARED | MAP_LOCKED | MAP_NORESERVE,<BR /> fd_mem, ddrPhyAddress);<BR /> if ((void *)ddrStart == MAP_FAILED)<BR /> {<BR /> close(fd_mem);<BR /> printf("mmap memory failed\n");<BR /> return -1;<BR /> }</P></BODY></HTML> Thu, 14 Sep 2017 03:44:13 GMT https://community.nxp.com/t5/PowerQUICC-Processors/linux-aio-with-mmap/m-p/703276#M2198 silecy2016 2017-09-14T03:44:13Z