Messages in this thread | | | Date | Wed, 6 Oct 1999 11:42:40 +0200 | From | Jan Kara <> | Subject | Re: clearing buffer cache |
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Hello. > I want to do some testing with an application where I need to see how long it > takes to read various scattered user data files from disk. I want to be able to > run the program whenever I want with the buffer cache empty of those user data > files. > > The only way I know to do this is just reboot the system before I run the > program each time, but that is really annoying. I went searching the > documentation and found the /proc/sys/vm/buffermem file which specifies the > min_percent, borrow_percent, and max_percent of memory to use for the buffer > cache. I thought I could temporarily set the max_percent really low and then > cause a bunch of disk IO on some other files. However, the kernel documentation > disagrees about that file: the Documentation/sysctl/vm.txt file says that the > borrow_percent and map_percent fields are unused, while the > Documentation/proc.txt file makes no note of them being unused. > > Another idea just to mind... what if I mount and un-mount the filesystem > containing the user files. Would that effect a buffer cache clearing for all > inodes on that filesystem? This should work... All buffers and inodes should be invalidated on unmount.
Honza.
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