[svlug] Performance and memory

[James Sparenberg]

On Fri, 2005-04-29 at 15:52 -0700, Jeffrey Siegal wrote:
> By the way, you asked about the OS taking advantage of the extra 
> memory.  In your case, it looks like your applications are using 
> something like 512 MB of memory, so you could almost certainly use 
> close to that (some small amount of swapping is harmless, as startup 
> routines and such that don't need to stay in memory after they're used 
> once get swapped out).  But beyond that, Linux will use the rest of 
> your memory to cache file system data.  So all sorts of file operations 
> will go a lot faster if you have "extra" memory.  Most of my Linux 
> systems now have 2 GB of RAM with less than half of that being used by 
> applications.  The rest is used to cache the file system.
> 

Not to take a single thing away from what is being said.  But also keep
in mind that with the improvements in ACPI and APIC in the new kernels
(as in it's working right wooo hooo!) you may be "suffering" from
Harddrive spin down.  In which case when you suddenly switch apps, it
takes 5-10 seconds for the drive to "wake up"   Combine that with any
need to swap that you have and this could be your "fun".  

Man hdparm to find out how to adjust this spindown time if it's getting
in your way.

James


James