Re: how to turn off, or to clear read cache?

[mru@users.sourceforge.net (Måns Rullgård)]

Luciano Miguel Ferreira Rocha <luciano@lsd.di.uminho.pt> writes:

>> >>> I need to make some performance tests. I need to switch off or to
>> >>> clear read cache, so that consequent reading of the same file will
>> >>> take the same amount of time.
>> >>>
>> >>>Is there an easy way to do it, without rebuilding the kernel?
>> >> Unmount and remount the filesystem.
>> >
>> >
>> > Would
>> >
>> > # mount -o remount
>> >
>> > do the job?
>> 
>> no
>
> What about dd if=/dev/hda bs=8M count=$(awk '/MemTotal/ { printf "%d", $2/4096 }' /proc/meminfo) ?
>
> Will it clear the cache?

It will probably clear some cache to make room for cache from hda.

perl -e '@f[0..100000000]=0'

will do it faster.

-- 
Måns Rullgård
mru@users.sf.net