Poor swapping performance -- lot's of unused free memory.

Marcin Koziej creep at desk.pl
Thu Jun 22 12:35:37 UTC 2006

I use FreeBSD 6.1-STABLE #0: Mon Jun 12 18:00:56 CEST 2006
for a desktop (Launch several apps at the start and mostly nothing else, 
except when compiling). I've got 512 MB of ram.

 From some time, I've noticed poor swapping performance -- this can be 
very annoying when memory needs to be swapped in and the whole systems 
chokes on disk I/O. Most frequently when launching a big application or 
clicking on recently not used application window.

What I notice, is that top(1) reports: 60 MB free, and 150 MB on the 
swap, which means these 60 mb are just sitting there doing nothing.
I remember in older versions of FreeBSD tried to keep swap as little 
used as possible, leaving 3-4 mb ram free. This is just a feeling, of 
course, but it feels like it's slower now.

Can anybody comment on this?
Maybe there is a sysctl which can tune this ? (I've searched for such, 
but found nothing).

Best regards,
Marcin Koziej

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