Re: Autotune swappiness01

[Con Kolivas]

Andrew Morton writes:

> Joel Becker <Joel.Becker@xxxxxxxxxx> wrote:
> > On Mon, Jul 26, 2004 at 10:43:01AM +1000, Con Kolivas wrote:
> > > Low memory boxes and ones that are heavily laden with applications find 
> > > that ends up making things slow down trying to keep all applications in 
> > > physical ram.
> >
> > 	Lowish memory boxes with plain desktop loads find that the default
> > of '60' is a terrible one (I'm speaking of 1GHz-ish machines with 256MB
> > (like mine) or 512MB (like a guy next to me)).  Every person I know who
> > installs 2.6 complains about how it feels slow and choppy.  I tell them
> > "The first thing I do after installing 2.6 is set swappiness to '20'."
> > Sure enough, they set swappiness to 20 and their box starts behaving
> > like a properly tuned one.
> > 	I don't know what workload the default of '60' is for, but for
> > the (128MB < x < 1GB) of RAM case, it sucks (and I've seen the same
> > behavior on a 300MHz 196MB box).
>
> Yes, I think 60% is about right for a 512-768M box.  Too high for the
> smaller machines, too low for the larger ones.

Sigh.. 

I have a 1Gb desktop machine that refuses to keep my applications in ram 
overnight if I have a swappiness higher than the default so I think lots of 
desktop users with more ram will be unhappy with higher settings.

> More intelligent selection of the initial value is needed.

Perhaps, but I really doubt desktop users running mainline would be happy 
about it going significantly higher. 

Cheers,
Con

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/