Swappiness default

[Rashkae]

On 05/23/2011 10:51 AM, Hakan Koseoglu wrote:
>
> Setting the swappiness to 0 delays any swaps until you've run out of
> RAM completely and only then it starts writing to disk. As a result if
> you have a lot of RAM, it's preferrable. On the other hand, when you
> run out of memory, it will start heavily swapping immediately (depends
> on how many processes want to grab the lot).
>
> If you set it to a high number, the system will housekeep very often
> and you will experience slow downs when you really don't need any (I
> have 2GB free, why are you swapping 1GB, oh the wise kernel?)...
>

Because using ram to cache frequently accessed files (such as mem-mapped 
libraries, as an example) is much better for overall system performance 
than holding little used pages of application ram.  Course, if you have 
objective benchmarks that contradict this...... (yeah, I know, I'm not 
providing any either.  But without proof otherwise, I'm going with the 
opinion of those who actually performance test the kernel with 
measurable metrics)

You should also keep in mind that a page is swap can also be in Ram at 
the same time.  Being in swap only means that that ram can be quickly 
paged out instantly at need.  Again, overall better system speed is 
achieved.