clear or disable file cache

acristescu · 10-26-2005, 08:43 AM

Hi,

I'm trying different methods to optimize a piece of java-written software. So I've setup some test data and processed it using all the methods I wanted to test. The problem is, I'm using the same data (it's a lot of data, hard to replicate) and all the tests after the first run very quickly (much more quickly than normal).

I figured this might be because Linux caches the files the first time they are accessed, so the second, third... tests don't really read the files.

So I searched everywhere trying to find a way to clear this file cache (or as a last result disable the thing), but so far came out with nothing. Can someone help me out of this predicament?

Tinkster · 10-26-2005, 02:17 PM

Hi, and welcome to LQ!

You can't do either to the best of my knowledge..
The only work-around would be to load other stuff
(e.g. run a huge copy, one that exceeds the machines
physical RAM size) and then re-run your test sequence.

Cheers,
Tink

acristescu · 10-27-2005, 03:27 AM

Thanks, that's my best hope, I think...

I tried to do a

Code:

Runtime.getRuntime().exec("cat bigfile > /dev/null")

but for whatever reason that takes ages in JAVA. I'm reading a big file with java calls just before each test... the test results are closer to reality now, but I'd still love to have a better method...

deep_inp · 11-04-2005, 10:25 AM

If ur dat file is in some other partition
May be mounting and unmounting may help

Cheers
Sandeep