Here’s an example of reading the system dictionary file by memory-mapping it. #include<stdio.h>#include<sys/mman.h>#include<unistd.h>#include<fcntl.h>intmain(void){intfd=open("/usr/share/dict/words",O_RDONLY);size_tpagesize=getpagesize();char*region=mmap((void*)(pagesize*(1<<20...
mmap 允许应用程序直接从内存操作文件,减少了传统文件读写调用(如 read、write)的开销,因为这些操作涉及到用户空间和内核空间之间的数据拷贝。 C:通过mmap实现大页内存申请-理论 在mmap 调用中使用 MAP_HUGETLB 选项可以请求操作系统使用大页(如 2MB 或 1GB 页面)来进行内存映射。大页的优势在于: 减少TLB(转换后援...
注意:在使用mlock()函数时,我们需要确保指定的内存区域已正确分配并且足够大,以避免锁定错误的内存区域。 7. mmap
Files master LICENSE README mmap_alloc.c mmap_alloc_test.c Latest commit Claudio Scordino Usage of dma_alloc_coherent Sep 21, 2012 4ba696d·Sep 21, 2012 History History
mmap function for windows module machine type 'x64' conflicts with target machine type 'X86' More Than One Operator "+" matches these operands Motherboard serial number MS library for PDF print for a c++ window without any driver? MS MPI only creates one process. MSADO15.dll mscomm32.ocx ...
此外,不是所有的文件描述符都支持splice()函数。在某些情况下,你可能需要使用其他的零拷贝技术,比如mmap()和sendfile()。 3.3 C/C++ 中的零拷贝优化技巧 (Optimization Techniques of Zero-Copy in C/C++) 虽然零拷贝技术能有效地减少数据在内存中的拷贝次数,从而提高程序性能,但在实际应用中,我们还需要考虑更多...
A subsequent link to build the executable file can be directed to use that map by using the linker -Mmapfile option. It places each function from the executable file into a separate section. Reordering the subprograms in memory is useful only when the application text page fault time is ...
//也可以用fopen + fread + fclose,不过file_get_contents因为可以mmap,效率更高 $data = file_get_contents('file.dat', 'r'); for ($i = 0, $c = strlen($data); $i < $c; $i += $length) { $bianbian = unpack("$format", $data); ...
7._IO_SETBUF---宏展开后的具体实现:_IO_new_file_setbuf 在经过一系列跳转之后我们调用到了_IO_file_setbuf_mmap函数,然后到了_IO_new_file_setbuf,这里面是具体的实现 /* The 'setbuf' hook gives a buffer to the file. It matches the streambuf::setbuf virtual function. */ ...
read: generic_file_read, write: generic_file_write, ioctl: ext2_ioctl, mmap: generic_file_mmap, open: generic_file_open, release: ext2_release_file, fsync: ext2_sync_file, }; 但是,Linux 2.6推荐类似的代码应该尽量采用标准C的方式: ...