Memory upgrade and swap partition size

Kjel Anderson kjel.anderson at gmail.com
Tue Sep 26 15:22:01 EDT 2006


That's good advice. I am putting together a machine out of old parts at the
moment for my son to use. I have been playing with Xfce and found that to
work really quite well with a 733 PIII and 256MB Ram. I'll try a bigger swap
on that machine and see how it does. I am pretty comfortable with the way
that memory allocation works on the hardware side, but I wasn't sure if the
swap played a role in all cases. Since I put the 2GB of memory in my swap
usage has stayed at a fairly constant 19MB, and naturally the performance is
much better. Makes me wonder what is in there. I don't know if it is just my
install of KDE, but firefox seems like it has a memory leak. If I leave it
up and come back after the weekend, my memory usage is way up. Doesn't seem
to be the most efficient application in that way. It might be nice to have a
truly light browser for some of these older machines.

Kjel

On 9/26/06, Bill Sconce <sconce at in-spec-inc.com> wrote:
>
> On Tue, 26 Sep 2006 12:08:13 -0400
> Kjel Anderson <kjel.anderson at gmail.com> wrote:
>
> > Hey list,
> >
> > I am probably exposing my ignorance by asking this, but I have to
> remember:
> > there are no stupid questions, just stupid people.
> >
> > I just upgraded the RAM in my workstation from 1GB to 2GB. Will resizing
> the
> > swap partition to the general guideline of double installed memory make
> a
> > performance difference?
>
>
> Hey, Kjel -
>
> I subscribe to all the good information you've gotten in the earlier
> replies.
> (Which is basically that, suspend-to-disk etc. aside, the larger your RAM
> the LESS the need for swap space.)
>
> The "law of conservation of memory" is that when you add up all bytes
> which
> must be addressed to accomodate whatever combination of (possibly bloated)
> stuff you're running, you need to have that much memory available - in
> real
> RAM plus swap.
>
> It's the kernel's job to move stuff back and forth, making it look like
> you
> have enough memory when really some of it's being "faked" by disk.  The
> tradeoff is that the part of your memory living on disk is a lot slower
> than
> the real part.  (Which may or may not matter very much, depending on
> whether
> the kernel is forced to move it back and forth a lot or a little.  You
> could
> use a large number of Firefox tabs, for instance, with gigantic images in
> each one, yet you only need to display one of them at at time.  Swap is
> likely to be good enough in this case.)
>
> My offering to the discussion: the "general guideline", which I've heard
> and seen just as you have, is misleading to the point of near nonsense.
> The SMALLER your real memory the greater the need for swap.
>
> I recently resuscitated a Presario laptop, a decent machine except for
> having
> a maximum electrical capacity for real RAM of 384MB.  I had followed the
> old
> "2X" rule, and I lived with the consequences for longer than I'd like to
> admit.
> It would run OK for most things -- mostly Firefox browsing, in fact -- but
> when I opened just one tab too many you couldn't BELIEVE the performance
> impact.  The poor disk went into overdrive, activity light on nearly full
> bright as the kernel desperately thrashed things back and forth, trying to
> get an arrangement on disk which would free up just a few more bytes.
>
> One morning after a sufficient number of cups of coffee it dawned on me
> what
> was wrong:  that the "2X" rule was fatal for a 384MB machine and my greedy
> use of Firefox tabs.  I took a deep breath, wiped the disk, created a 2GB
> swap file and reinstalled.  It NEVER stalls now -- the first week or so I
> had to keep pinching myself how well the poor thing worked with "enough"
> memory at last.  And how dumb I'd been to ever credit "2X".  An old wives'
> tale...
>
> .02
>
> -Bill
> _______________________________________________
> gnhlug-discuss mailing list
> gnhlug-discuss at mail.gnhlug.org
> http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.gnhlug.org/mailman/private/gnhlug-discuss/attachments/20060926/4077a4e6/attachment.html


More information about the gnhlug-discuss mailing list