smart cache. ist is possible?

From: Alexey Fisher
Date: Sun Mar 15 2009 - 11:29:15 EST


Hallo all.
I found for my self how great is cache in linux. If read one file from
disk, so i don't need to do it second time, chace will do the job. It
speed up thing greatly. But i found it not working with realy big files.
Like i have 4GB RAM, so if i read a file like 4.6GB, cache won't work.
Is it possible to have some sort of smart cache wich will read for
exaplme 1GB from disk and other part from cache?

here is some simple test:
=====================cache not working==========================
dd if=dvd.iso of=/dev/null
9017680+0 DatensÃtze ein
9017680+0 DatensÃtze aus
4617052160 Bytes (4,6 GB) kopiert, 90,7817 s, *50,9 MB/s*

dd if=dvd.iso of=/dev/null
9017680+0 DatensÃtze ein
9017680+0 DatensÃtze aus
4617052160 Bytes (4,6 GB) kopiert, 90,7817 s, *50,9 MB/s*
===============================================================


=====================cache working============================
dd if=film.avi of=/dev/null
1432600+0 DatensÃtze ein
1432600+0 DatensÃtze aus
733491200 Bytes (733 MB) kopiert, 15,5108 s, *47,3 MB/s*

dd if=film.avi of=/dev/null
1432600+0 DatensÃtze ein
1432600+0 DatensÃtze aus
733491200 Bytes (733 MB) kopiert, 0,941367 s, *779 MB/s*
==============================================================
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