Re: [SLUG] winswap as linux swap

From: Steve (steve@szmidt.org)
Date: Sun Aug 24 2003 - 15:53:34 EDT


On Sunday 24 August 2003 12:20 pm, you wrote:
> On Sun, 24 Aug 2003 02:41:19 -0400
>
> Steve <steve@szmidt.org> wrote:
> > On Sunday 24 August 2003 02:28 am, you wrote:
> > > On Saturday 23 August 2003 09:49 pm, you wrote:
> > > > There's a way to use windows swap as your linux swap??
> > > > I have a 1 gig swap partition (yeah i know that huge, but i have
> > > > the space and use graphics/music/video apps ;) ) I also have a
> > > > seperate linux swap partition. Anyone have a link on how to do
> > > > this. I have a seperate partition for photoshops swap, and am going
> > > > to try to use this as swap for the gimp as well. It's fat32. Thanx
> > >
> > > No no no! This is NUTS! I mean I've never tried it but it sounds
> > > crazy!
> >
> > Maybe I got this wrong. Are you talking about swap for GIMP? Why have a
> > special partition for that? What's the benefits? I've never looked into
> > that for GIMP, but ext2/ext3 is very efficient with not letting files
> > get defragged.
> >
> > --
> >
> > Steve
>
> I have a seperate swap partition already for photoshop in windows. I
> figure Since I already have this partition, i might as well try it for
> the gimp. I haven't tried it yet though. So your saying that if my swap
> file is too big it will actually degrade performance? I'v never heard
> that. No i really don't swap that much, and have actually had an install
> that had no swap at all. Both seemed to run about the same. iirc i did
> run into a problem once or twice when I had no swap though, but on
> average it was like butter. I have 512MB of pc2700 ddr ram btw.

No not your swap file, though that is true too. (The reason you're not
noticing too much difference is due to the slowness of windows in general.)

To paraphrase what I said; to the degree that a swap partition is used, to
that degree the computer will run slower. The reason is obvious. RAM speed
is measured in ns (nano seconds - 1,000,000,000 parts of a second) versus a
disk technology which is measured in ms (milli seconds 100 parts of a
second). To extend RAM into swap means a delay of a million times slower
per instruction or data.

You can test it by removing half your RAM. Load photoshop up as you did
before. If you have w2k (it really wants 256M for it self) you should
notice a difference pretty fast.

It may not seem that much due to 1) human inability to tell milli seconds
apart from nano seconds 2) there is more going on than just reading RAM.

The computer accessing a swap disk to process data may still need to read it
from the data partition. So we are only adding the million times lag on
processing instructions not reading the disk for data. It quickly does add
up to a visiable lag the more it needs to do it.

Under windows it has a less efficient swap system, i.e. the file which is
under a non swap optimized filesystem. Whereas a swap partition is
optimized to only extend RAM.

I have on occation setup a partition that I decided to only use for
photoshops swap file too (under windows now). Photoshop (unlike windows)
supports placing the swap file on different drives.

At this point we have three different swap areas. We have two operating
systems swap systems and an application swap file. They are not the same.

Photoshop is not directly swapping RAM. It is saying that when I cannot get
more RAM to hold my images to start reading and writing to a swap file
instead. It is probably controlled by the app not the O/S. (I really don't
know this for sure but is my educated guess. Theoretically the app could be
calling on windows to do the swapping. Though it does not seem too likely
that you can or would want that. Windows have enough problems managing
memory without adding another thing to it. But again that's just my guess.)

-- 

Steve _________________________________________________ This sig is pending approval by SCO's legal team. Licensing fee's expected to be "fair", i.e. $999. ----------------------------------------------------------------------- This list is provided as an unmoderated internet service by Networked Knowledge Systems (NKS). Views and opinions expressed in messages posted are those of the author and do not necessarily reflect the official policy or position of NKS or any of its employees.



This archive was generated by hypermail 2.1.3 : Fri Aug 01 2014 - 18:32:53 EDT