Question

When running performance tests file system cache hit or miss can significantly influence test results. Therefore generally before running such tests used files are evicted from system cache. How to do that on Linux?

Clarification: If possible, the solution should not require root privileges.

Answer 1

Ha, I have the answer:

#include <unistd.h> #include <fcntl.h> int main(int argc, char *argv[]) {   int fd;   fd = open(argv[1], O_RDONLY);   fdatasync(fd);   posix_fadvise(fd, 0,0,POSIX_FADV_DONTNEED);   close(fd);   return 0; } 

This is from http://insights.oetiker.ch/linux/fadvise.html