Is a directory considered a file?
“… directory is actually no more than a file, but its contents are controlled by the system, and the contents are names of other files. (A directory is sometimes called a catalog in other systems.)”
How does vmtouch work?
vmtouch opens every file provided on the command line and maps it into virtual memory with mmap(2). The mappings are opened read-only. It recursively crawls any directories and does the same to all files it finds within them. With no options, vmtouch will not read from (touch) any memory pages.
What is Vmtouch?
vmtouch is a tool that can “lock” a file in disk cache. It benefits applications that need to perform fast random access to large files (i.e. several gigabytes). We’ve made a slight modification to the source code to allow for larger files to be cached.
Does Linux cache files in memory?
Linux always tries to use RAM to speed up disk operations by using available memory for buffers (file system metadata) and cache (pages with actual contents of files or block devices). This helps the system to run faster because disk information is already in memory which saves I/O operations.
How many pages in vmtouch Big dataset.txt?
$ vmtouch -v big-dataset.txt big-dataset.txt [ oOOOOOOO] 4950/42116 Files: 1 Directories: 0 Resident Pages: 4950/42116 19M/164M 11.8% Elapsed: 0.006706 seconds vmtouch tells us that 4950 pages at the end of the file are now resident in memory.
What do you need to know about vmtouch?
vmtouch is a tool for learning about and controlling the file system cache of unix and unix-like systems. It is BSD licensed so you can basically do whatever you want with it.
How to check if a directory contains a file?
DirectoryInfo d = new DirectoryInfo (path); if () // there is a file in the directory do something. I can get the files if there exists any, but I also have to consider the possbility that there is no file inside that subfolder path.