![]() ![]() Large file blocks don't tend to stay in the cache for very long anyway, unless you have a ton of memory relative to the file size. The performance penalty with buffered I/O is substantially worse for large files. The usage note mentions large files vis-à-vis buffered I/O because: The operating system takes care of synchronizing file writes back to disk, and reads can be pulled directly from memory. Buffered I/O incurs a performance penalty the first time the file is accessed because it has to copy the file into memory however, because memory access is faster than disk access, subsequent file access should be faster. Buffered I/O augments the simple copy to optimize for future reads of (and writes to) the same file by copying the file into the filesystem cache, which is a region of virtual memory. Unbuffered I/O is a simple file copy from a source location to a destination location.
0 Comments
Leave a Reply. |