Re: striped swapping?

Steve Payne (srp20@cam.ac.uk)
Tue, 30 Apr 1996 18:16:02 +0100 (BST)

> > > If I have two swap partitions on two separate hard drives (on separate
> > > busses) under linux is the swapper clever enough to strip (even corsely
> > > (sp?)) bewteen them? (I'm guessing you _can_ have more than one swap
> > > partition active at once).
> >
> > Yes, IF you are using the new swapon from util-linux-2.5 or later, AND
> > you use the new priority flags to give both your swap partitions the
> > same priority. If you don't do this, then the earlier installed
> > partitions will be swapped to in preference to the later ones.
> >
>
Well, I now have two swap partitions running together at the same
priority. Here are the results of two simultanious Modula 3 compiles
(with the striping and without):

Before:

10.86user 0.85system 2:27.52elapsed 7%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (5758major+3193minor)pagefaults 1776swaps

10.40user 0.89system 2:26.71elapsed 7%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (5990major+3184minor)pagefaults 1727swaps

( 147.52/1776 = 0.0830 )

After:

7.49user 0.80system 1:48.13elapsed 7%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (4523major+2031minor)pagefaults 1507swaps

7.51user 0.77system 1:47.86elapsed 7%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (4415major+2035minor)pagefaults 1519swaps

( 108.13/1519 = 0.0711 )

and...for those interested

total used free shared buffers cached
Mem: 14960 10632 4328 5216 404 4880
-/+ buffers: 10228 4732
Swap: 95720 8348 87372

Linux igor 1.3.93 #1 Tue Apr 30 16:13:05 BST 1996 i586
(100Mhz)

Looks like it made a difference :)

srp

--
  Stephen Payne             -  "Hey, I've just invented a great new sound..."
 srp20@cam.ac.uk            -            "Untie Neil's legs Vyvyan"